•       THE 

ENGLISH  AND  FOREIGN 

PHILOSOPHICAL  LIBRARY. 


VOLUME  XIV. 


Los  Angeles,  Cal. 

THE    COLOUE-SENSE: 

Its  (25rtgtn  anH  aDeUelopment. 

AN  ESSAY  IN  COMPARATIVE  PSYCHOLOGY. 


BY 


GKANT    ALLEN,    B.A. 

AUTHOR  OK  "physiological  AiSTHKTlCS." 


BOSTON: 

HOUGHTON,    OSGOOD,    &    COMPANY. 

1879. 


4tei 


1^0 


/<?71 


PREFACE. 


The  materials  which  form  the  nucleus  of  the  present 
volume  were  originally  collected  as  part  of  the  basis  for  a 
chapter  on  "  the  Genesis  of  Esthetics  "  in  my  little  work 
on  "  Physiological  Esthetics,"  published  some  two  years 
since.  I  found,  however,  when  I  came  to  arrange  them, 
that  the  subject  had  grown  under  my  hands,  and  that  it 
would  be  impossible  fully  to  develop  my  ideas  except  in 
the  form  of  a  separate  treatise.  The  omission  seemed  all 
the  more  desirable,  because  my  former  work  dealt  only 
with  Esthetics  as  an  element  of  human  psychology  : 
while  the  materials  here  collected  refer  rather  to  the 
wider  science  which  studies  the  phenomena  of  mind 
throughout  the  whole  animal  world.  Accordingly,  I  de- 
ferred their  publication  for  the  time,  only  mentioning  my 
original  intention  in  a  footnote  on  p.  156  of  "Physio- 
logical Esthetics."  But  most  of  the  critics  who  kindly 
noticed  that  little  work  were  so  unanimous  in  calling  at- 
tention to  the  hints  which  I  had  thrown  out  with  reference 
to  the  Colour-Sense,  and  the  love  for  colour  which  forms 
such  a  striking  characteristic  of  mankind,  that  I  determined 

on  f  olio  win  c^  up  the  subject  on  a  wider  basis,  and  eluci- 

h 


vi  PREFACE.  ' 

dating  my  view  by  full  inductive  generalisations.     The 
present  volume  is  the  result. 

Meanwhile  two  works  appeared,  in  Germany  and  in 
England,  which  necessitated  considerable  divergences 
from  my  original  plan.  The  first  was  Dr.  Hugo  Magnus's 
"  Geschichtliche  Entwickelung  des  Tarbensinnes ; "  the 
second  Mr.  A.  K.  Wallace's  "Tropical  JSTature."  Put  shortly, 
the  gist  of  my  theory  was  this :  that  the  taste  for  bright 
colours  has  been  derived  by  man  from  his  frugivorous 
ancestors,  who  acquired  it  by  exercise  of  their  sense  of 
vision  upon  bright-coloured  food-stuffs ;  that  the  same 
taste  was  shared  by  all  flower-feeding  or  fruit-eating 
animals ;  and  that  it  was  manifested  in  the  sexual  selection 
of  brilliant  mates,  as  well  as  in  other  secondary  modes, 
such  as  the  various  human  arts.  The  two  volumes  men- 
tioned above  came  like  utterly  destructive  criticisms  of 
any  such  belief.  Dr.  Magnus  endeavoured  to  prove  that 
the  Colour-Sense  of  mankind  was  a  late  historical  acqui- 
sition of  the  race,  whose  beginnings  hardly  dated  back  as 
far  as  the  Homeric  and  Vaidik  periods.  Mr.  Wallace  con- 
troverted, with  all  his  well-known  vigour  and  ingenuity, 
the  theory  of  sexual  selection,  first  announced  by  Mr. 
Darwin,  upon  which  rested  almost  the  whole  argument 
for  a  love  of  pure  colour  among  the  lower  animals.  Thus 
these  two  books  between  them  cut  away  the  whole  ground 
from  under  my  feet.  It  became  necessary  to  go  back  over 
my  materials  afresh,  and  to  seek  for  evidence  against  both 
anticipatory  assailants.  I  have  tried,  therefore,  to  show, 
in  opposition  to  Dr.  Magnus,  that  the  Colour-Sense  of 
mankind  dates  back  to  the  earliest  appearance  of  our  race 


PREFACE.  vii 

upon  earth ;  and,  in  opposition  to  Mr.  Wallace,  that  a 
modified  form  of  the  sexual  selection  theory  may  still 
survive  his  powerful  attack.  I  am  aware  how  ill  prepared 
I  am  to  encounter  so  thorough  a  biologist  as  the  joint  dis- 
coverer of  Natural  Selection  on  his  own  ground ;  but  I 
have  humbly  offered  such  arguments  as  lay  in  my  power, 
trusting  to  the  generosity  of  my  opponent  to  forgive  any 
technical  errors  which  may  easily  creep  into  a  discussion 
of  the  sort. 

I  should  like  to  add  that  I  enter  the  lists  as  a  compara- 
tive psychologist,  not  as  a  biological  student.  I  do  not 
pretend  to  discover  facts  of  botany  or  zoology  at  first 
hand :  I  accept  them  as  data  from  the  lips  of  competent 
specialists.  Yet  I  hope  my  work  may  prove  valuable  in 
its  own  peculiar  sphere,  which  ought  to  be  kept  distinct 
from  the  objective  biological  sciences  whose  conclusions 
form  its  basis.  Our  great  naturalists  supply  us  with  the 
facts  upon  which  to  build  our  comparative  psychology : 
and  I  hope  there  is  no  presumption  in  employing  them 
sometimes  to  test  the  logical  correctness  of  a  few  among 
the  naturalists'  own  conclusions. 

One  of  the  main  necessities  of  science  at  the  present 
day  is  the  existence  of  that  organising  class  whose  want 
was  pointed  out  by  Comte,  and  has  been  further  noted  by 
Mr.  Herbert  Spencer.  To  this  class  I  would  aspire,  in  a 
humble  capacity,  to  belong.  But  the  organising  student 
cannot  also  himself  be  a  specialist  in  all  the  sciences 
whose  results  he  endeavours  to  co-ordinate  :  and  he  must, 
therefore,  depend  for  his  data  upon  the  original  work  of 
others.     If   specialists   find  technical  errors  in  such  co- 


viii  PREFACE. 

ordinated  results,  they  should  point  them  out  frankly  for 
correction  and  improvement,  but  they  should  not  regard 
them  as  fit  subjects  for  carping  criticism.  I  shall  feel 
grateful  to  any  biologists  who  can  suggest  alterations  or 
modifications  in  any  part  of  what  I  cannot  but  feel  a  very 
tentative  and  rudimentary  work.  But  unless  we  make  a 
beginning  in  psychology  we  shall  never  reach  the  end : 
and  I  send  forth  my  speculations  rather  in  the  hope  that 
they  may  arouse  comment  and  lead  to  further  researches, 
than  because  I  consider  them  in  any  way  final  or  com- 
plete. 

With  regard  to  the  authorities  used  or  quoted,  I  have 
followed  the  plan  of  making  no  references  to  original 
works  when  dealing  with  the  accepted  common-places  of 
science ;  but  wherever  I  have  occasion  to  note  a  particuW 
fact,  of  comparatively  modern  ascertainment  or  specialist 
knowledge,  I  give  the  authority  in  a  footnote.  For  the 
general  groundwork  of  my  theory,  my  acknowledgments 
are  mainly  due  to  the  works  of  Mr.  Darwin  and  Mr. 
Herbert  Spencer,  which  I  seldom  quote  by  name,  because 
they  now  form  part  of  the  established  body  of  scientific 
doctrine.  After  these,  I  owe  most  to  Mr.  A.  R  Wallace, 
Mr.  Bates,  and  Mr.  Belt.  For  personal  assistance,  by  letter 
or  otherwise,  I  must  thank  Mr.  Darwin,  who  supplied  me 
with  corrections  on  the  colours  of  flowers ;  Mr.  Wallace, 
who  kindly  wrote  to  me  with  regard  to  the  colours  of 
fruits;  Mr.  Galton,  F.E.S.,  for  an  introduction  to  the 
library  of  the  Eoyal  Society ;  Mr.  Gladstone,  who  called 
my  attention  to  notes  in  German  periodicals ;  the  Eev.  A. 
H.  Sayce,  for  reference  to  Assyrian  and  Babylonian  works 


PREFACE,  IX 

of  art ;  the  Eev.  T.  K.  Cheyne,  for  aid  on  the  question  of 
Hebrew  colour-terms ;  Mr.  H.  N.  Moseley,  naturalist  to 
the  Challenger  expedition,  for  references  to  papers  on  the 
colouration  of  deep-sea  organisms ;  Sir  John  Lubbock  and 
Mr.  B.  T.  Lowne,  for  copies  of  their  original  researches  on 
the  eyes  and  optical  perceptions  of  insects ;  and  the  Eev. 
S.  J.  Whitmee  of  Samoa,  with  a  large  number  of  other 
missionaries  or  civil  servants,  for  information  with  regard 
to  the  Colour- Sense  of  savages. 

In  a  more  strictly  personal  sense,  I  owe  my  acknow- 
ledgments to  my  friends,  Mr.  F.  T.  Eichards  of  Trinity 
College,  Oxford,  Mr.  G.  J.  Eomanes,  F.L.S.,  and  Professor 
G-  Croom  Eobertson,  for  constant  assistance  in  calling  my 
attention  to  passages  in  books  or  periodicals  which  bore 
on  the  subject  under  investigation. 

Finally,  I  should  mention  that,  although  most  of  the 
matter  contained  in  the  present  volume  is  entirely  new,  I 
have  incorporated  into  Chapters  IV.  and  VI.  the  substance 
of  two  papers  on  "  The  Origin  of  Flowers  "  and  "  The  Origin 
of  Fruits,"  which  appeared  in  the  "  Cornhill  Magazine  " 
for  May  and  August  1878.  Part  of  the  materials  for 
Chapter  X.  were  also  included  in  a  note  which  I  con- 
tributed to  "  Mind  "  for  January  of  the  same  year. 

G.  A. 


CONTENTS 


CHAPTER  I.  I 

1 

INTRODUCTORY  ......  I  1 


CHAPTER  n.  : 

I 

^THER-WAVES  AND  THEIR  VARIETIES  ...  7  \ 


CHAPTER  III.  ; 

THE  ORGAN  OF  VISION  .....  23  I 

1 

CHAPTER  IV.  i 

INSECTS  AND  FLOWERS  .  .  .  .  •  33  | 

CHAPTER  V. 

THE  COLOUR-SENSE  IN  INSECTS  .  .  .  .  8 1  I 

CHAPTER  VI.  ; 

I 

BIRDS  OR  MAMMALS  AND  FRUITS  ....  97  j 

! 

CHAPTER  VII.  - 

THE  COLOUR-SENSE  IN  VERTEBRATES  .  .  •  117 

CHAPTER  VIII.  ; 

THE   COMMUNITY    OF    TASTE   BETWEEN   FLOWER-FEEDING   AND 

FRUIT-EATING  SPECIES  .  .  .  .  I29  I 


CONTENTS. 


CHAPTER  IX. 

THE   DIRECT    REACTION     OF   THE    COLOUR-SENSE    UPON    THE 
ANIMAL  INTEGUMBNTS  .... 


[49 


CHAPTER  X. 

THE  INDIRECT  REACTION  OF   THE   COLOUR-SENSE   UPON  THE 

ANIMAL  INTEGUMENTS  .  .  .  .  I95 

CHAPTER  XI. 

THE  COLOUR-SENSE  IN  MAN      .....  202 

CHAPTER  XII, 

THE  ^ESTHETIC  VALUE  OF  COLOUR        ,  .  .  .22'' 


CHAPTER  XIII. 

THE  GROWTH  OF  THE  COLOUR- VOCABULARY   . 

CHAPTER  XIV. 

SUMMARY  AND  RECAPITULATION 


!5o 


79 


THE     COLOUR-SENSE. 


CHAPTER  I. 

I  N  T  R  O  D  U  C  T^O  R  Y. 

There  is  no  element  of  our  sensuous  nature  wliicli  yields 
us  greater  or  more  varied  pleasure  than  the  perception 
of  colour.  Whether  we  look  at  the  larger  physical  wholes, 
the  azure  heaven  above  us,  the  purple  sea  beneath  us, 
and  the  green  meadows  by  our  side ; — or  at  the  smaller 
organic  bodies,  the  brilliant  flowers,  the  crimson  foliage  of 
autumn,  the  gaudily  painted  butterflies,  the  beetles  clad 
in  burnished  gold,  the  peacock  adorned  with  all  the  hues 
of  the  rainbow,  and  the  humming-birds  decked  out  in 
ruby,  sapphire,  and  amethyst ; — or  again  at  the  transient 
effects  of  light  in  the  spectrum,  the  soap-bubble,  the 
iridescent  surface  of  the  opal,  the  tints  of  eventide  mir- 
rored in  the  glassy  lake ; — in  each  and  every  case  we  feel 
a  thrill  of  pure  and  unselfish  enjoyment,  which  no  other 
mere  sensuous  stimulation  is  capable  of  arousing  in  our 
breasts.  '.The  pleasure  of  colour  is  one  which  raises  itself 
above  the  common  level  of  monopolist  gratification,  and 
attains  to  the  higher  plane  of  aesthetic  delightJ 

ISTor  is  man  the  only  creature  who  can  appreciate  and 
enjoy  the  lavish  store  of  beauty  which  nature  pours  forth 
for  his  pleasure  in  the  fields  and  the  forest.  We  shall  see 
reason  to  conclude,  from  the  facts  collected  in  this  volume, 

A 


2  THE  COLOUR-SENSE, 

that  many  of  our  dumb  relations  can  fully  enter  into  the 
love  for  exquisite  colour,  at  least  in  its  simplest  and 
earliest  forms.  We  shall  find  good  ground  for  believing 
that  the  bird  of  paradise  does  not  display  its  gorgeous 
plumage  to  the  careless  eyes  of  an  unobservant  mate ; 
that  the  gaily  painted  butterfly  is  not  insensible  to  the 
lovely  tracery  upon  the  wings  of  its  fellow ;  and  even  that 
the  tropical  lizards  or  batrachians  can  duly  admire  the 
glistening  coats,  crimson  crests,  or  golden' pouches  of  their 
lissome  helpmates.  We  shall  further  note  certain  habits 
which  may  lead  us  to  suspect  that  birds  and  insects  are 
pleasurably  affected,  not  only  by  the  colour  of  their  own 
kind,  but  also  by  the  delicate  or  brilliant  tints  of  the 
fruits  and  flowers  upon  which  they  feed.  In  short,  our 
object  must  be  to  trace  back  the  pleasure  which  man 
experiences  from  the  deft  combination  of  red  and  green 
and  violet,  in  painting  or  in  decorative  art,  to  a  long 
line  of  ante-human  ancestry,  stretching  back  indefinitely 
through  geological  ages  to  the  first  progenitors  of  verte- 
brate life. 

More  than  this  we  must  attempt  to  show.  If  we  would 
learn  fully  the  whole  history  of  the  colour- sense,  we 
must  track  it  backward  through  the  generations  of  the 
earlier  earth,  till  we  discover  what  were  the  circumstances 
by  which  it  was  first  produced.  We  must  find  out  how 
the  various  modes  of  sether-waves,  which  we  now  know 
as  colours,  came  originally  to  be  distinguished  from  one 
another  by  the  nascent  eyes  of  half-developed  reptiles 
and  insects.  We  must  see  by  what  steps  the  hues  of 
flowers,  and  seeds,  and  fruits,  and  small  animal  prey 
caused  the  growth  of  a  distinctive  colour-perception  in 
the  creatures  which  fed  upon  them.  And  we  shall  pro- 
bably conclude  at  the  same  time  that  the  sense  thus 
developed  became  in  turn  a  source  of  new  pleasure  to 
its  possessors,  and  a  groundwork  for  more  marvellous 
developments  in  future.  The  taste  which  was  formed  by 
the  lilies  and  roses,  the  golden  oranges  and  purple  grapes, 


INTRODUCTORY.  3 

ended  by  producing  the  metallic  lustre  of  tlie  sunbirds  and 
the  daintily  shaded  ornamentation  of  the  argus-pheasant. 
We  may  hope  to  show,  furthermore,  that  the  existence 
of  bright  colouring  in  the  world  at  large  is  almost  entirely 
due  to  the  influence  of  the  colour-sense  in  the  animal 
kingdom.     I  do  not  mean,  of  course,  that  animals  have 
anything  to  do  with  the  objective  existence  of  those  dif- 
ferent aether-waves  in  the  pencil  of  light  which,  when 
decomposed  or  separated,  we  perceive  as  colours ;  nor  do 
I  mean  to  include  in  this  category  the  shades  of  earth, 
sea,  sky,  and  other  great  inorganic  masses.     Obviously 
the  human  or  animal  eye  could  have  no  influence  upon 
their  origin  or  colouring.     Even  the  green  leaves  of  the 
trees  and  grasses  seem  quite  independent  of  man  or  beast. 
But  I  still  think  that  a  vast  mass  of  the  coloured  objects 
with  which  we  are  most  familiar  owe  their  hues  to  the 
perceptions  of  some  insect,  bird,  or  animal.     If  we  look 
briefly  at  a  few  of  the  best-known  cases,  the  reader  will 
more  clearly  comprehend  the  line  of  argument  which  this 
book  proposes  to  itself. 

In  the  drawing-room  where  we  sit,  every  object  has 
obtained  its  colour  entirely  with  reference  to  the  likes 
and  fancies  of  humanity.  Not  only  have  the  pictures 
and  ornaments  been  painted  so  as  to  please  our  eyes,  but 
the  carpets,  the  wall-paper,  the  curtains,  the  table-covers, 
the  embroidery,  the  damask  on  the  chairs  and  sofas,  the 
clothing  of  the  women  and  children,  have  all  been  dyed 
on  purpose  to  stimulate  and  gratify  the  sense  of  sight. 
Indeed,  there  is  scarcely  an  article  of  human  use  and 
manufacture,  from  the  vermilion-stained  earthenware  of 
the  prehistoric  savage  and  the  woad  adornment  of  the 
Cymric  warrior,  to  the  Lambeth  and  Vallauris  pottery,  or 
the  cretonnes  and  crewel-work  of  modern  aesthetic  de- 
signers, which  has  not  received  some  special  manipulation 
to  add  pleasing  colour  by  means  of  dyes  or  pigments. 
The  universal  effect  of  the  colour-sense  on  human  pro- 
ducts is  too  obvious  to  need  further  illustration. 


4  THE  COLOUR-SENSE. 

A  step  lower  down,  we  reach  the  actual  bodies  of  men 
and  animals  themselves.  It  would  seem  at  first  sight  as 
thouo:h  the  colour-sense  could  have  nothing  to  do  with 
the  production  of  these.  Yet  the  theory  of  sexual  selec- 
tion, into  which  we  shall  enter  more  fully  hereafter,  shows 
us  how  the  long-continued  choice  of  beautiful  mates  may 
have  had  the  effect  of  encouraging  the  growth  of  bright- 
hued  individuals,  and  the  obsolescence  of  their  less 
favoured  fellows.  I  shall  try  to  point  out,  also,  an  adjunct 
to  this  theory,  which  seems  to  have  escaped  even  the  keen 
eyes  of  Mr.  Darwin,  Mr.  Wallace,  and  their  German 
allies.  I  shall  endeavour  to  prove  that  only  those  animals 
display  beautiful  colours,  due  to  sexual  selection,  in  whom 
a  taste  for  colour  has  already  been  aroused  by  the  influ- 
ence of  flowers,  fruits,  or  brilliant  insects,  their  habitual 
food.  As  the  liking  cannot  have  grown  up  without  some 
groundwork  of  advantage  to  be  gained  by  it,  we  might 
gather,  even  a  priori,  that  such  would  be  the  case ;  and  I 
hope,  in  the  sequel,  to  adduce  a  sufficiently  large  array 
of  positive  instances  to  justify  an  inductive  conclusion 
to  the  same  effect. 

Taking  still  another  step  backward,  we  arrive  at  the 
brilliantly  coloured  fruits  and  flowers,  upon  which  these 
tastes  were  formed.  And  here  we  shall  have  reason  to 
believe  that  the  agency  of  insects  has  been  most  powerful 
in  developing  the  hues  of  blossoms ;  while  the  fruits,  as 
we  shall  see,  are  rather  due  to  the  selective  action  of  birds 
and  mammals.  Between  them  almost  all  the  colours  of 
vegetal  life,  except  the  uniform  green  of  the  foliage,  are 
probably  produced,  being  due  to  the  colour-sense  of  one 
or  other  of  the  great  seeing  classes,  the  vertebrate  and  the 
articulate. 

Many  lesser  cases  may  be  alleged,  where  colours  have 
been  acquired  for  purposes  of  protection  or  deception,  and 
of  such  an  abundance  will  be  forthcoming  in  their  proper 
place.  But  enough  has  doubtless  been  said  to  show  the 
immense  importance  of  the  colour-sense  in  man  or  animals, 


INTRODUCTORY.  5 

and  the  conspicuous  part  which  (as  I  believe)  it  has  played 
in  the  moulding  of  organic  forms.  If  I  put  in  two  anti- 
thetical paragraphs  the  various  great  classes  of  coloured 
objects  which  we  do  or  do  not  owe  to  its  operation,  the 
reader  will  be  able  to  see  at  a  glance  just  how  much  influ- 
ence I  claim  for  it. 

We  do  not  owe  to  the  colour-sense  the  existence  in 
nature  of  the  rainbow,  the  sunset,  or  the  other  effects  of 
iridescent  light ;  the  blue  sky,  the  green  or  purple  sea,  the 
red  rocks,  or  the  other  great  inanimate  masses ;  the  foliage 
of  trees  and  shrubs,  the  hues  of  autumn,  and  the  tints  of 
precious  stones  or  minerals  generally. 

But  we  do  owe  to  the  colour -sense  the  beautiful  flowers 
of  the  meadow  and  the  garden, — roses,  lilies,  carnations, 
lilacs,  laburnums,  violets,  primroses,  cowslips,  and  daisies ; 
the  exquisite  pink  of  the  apple,  the  peach,  the  mango,  and 
the  cherry,  with  all  the  diverse  artistic  wealth  of  oranges, 
strawberries,  plums,  melons,  brambleberries,  and  pome- 
granates ;  the  yellow,  blue,  and  melting  green  of  tropical 
butterflies;  the  magnificent  plumage  of  the  toucan,  the 
macaw,  the  cardinal-bird,  the  lory,  and  the  honeysucker ; 
the  red  breast  of  our  homely  robin ;  the  silver  or  ruddy  fur 
of  the  ermine,  the  wolverine,  the  fox,  the  squirrel,  and 
the  chinchilla;  the  rosy  cheeks  and  pink  lips  of  English 
maidens;  the  whole  catalogue  of  dyes,  paints,  and  pig- 
ments ;  and,  last  of  all,  the  colours  of  art  in  every  age  and 
nation,  from  the  red  cloth  of  the  South  Seas,  the  lively 
frescoes  of  the  Egyptian,  and  the  subdued  tones  of  Hel- 
lenic painters,  to  the  stained  windows  of  Poitiers  and  the 
Madonna  of  the  Sistine  Chapel. 

The  origin  and  rise  of  this  powerful  sense,  and  the  means 
by  which  it  has  effected  all  these  marvellous  reactions  on 
the  external  world,  form  the  text  upon  which  we  must 
string  our  discourse  in  the  present  volume.  We  shall 
begin  with  the  nature  of  colour,  viewed  as  an  external  and 
objective  fact ;  we  shall  next  look  at  the  steps  by  which 
the  various  eyes  of  insects  and  animals  became  sensible  to 


6  THE  COLOUR-SENSE. 

its  diverse  stimulations ;  we  shall  then  proceed  to  ask 
what  secondary  effects  the  newly  acquired  sense  produced 
upon  the  surrounding  existences;  and  we  shall  finally 
examine  its  remote  aesthetic  results  in  the  sphere  of  human 
activity.  We  shall  thus  have  traced  the  perception  of 
colour  from  its  first  faint  beginnings  in  palaeozoic  seas  or 
carboniferous  forests  down  to  its  latest  developments  in 
the  palaces  or  galleries  of  civilised  man. 


(    7     ] 


CHAPTER   II. 

^THER-WAVES   AND   THEIR   VARIETIES.^ 

Befoee  we  can  investigate  any  sensation  in  men  or 
animals,  we  must  find  out  what  is  tlie  external  agency 
to  which  it  corresponds.  Every  feeling  answers  to  some 
outer  fact,  and  in  the  development  of  life  the  fact  must 
necessarily  have  preceded  the  feeling.  Unless  there  had 
been  matter  there  could  never  have  been  mind.  Without 
resistance  we  could  not  experience  touch;  without  air 
we  could  not  possess  hearing ;  without  aether  we  could 
not  have  developed  the  wonderful  faculty  of  sight. 
Organic  substances,  acted  upon  by  peculiar  agencies  in 
the  inorganic  world,  give  rise  to  the  phenomena  of 
sensation ;  but  we  cannot  understand  the  existence  of 
sensation  unless  we  previously  grant  the  existence  of 
an  influence  capable  of  developing  it.  Idealism,  which 
looks  fallaciously  plausible  when  applied  to  the  fully 
evolved  intelligence,  becomes  meaningless  and  self-con- 
tradictory when  applied  to  the  problem  of  its  evolution. 

1  In  the  short  sketch  of  Physical  mixture  of  pigments.  Such  questions 
Optics  which  follows,  I  have  en-  are  wholly  foreign  to  our  present 
deavoured,  not  to  give  a  resume  of  subject,  and  I  merely  note  the  omis- 
all  that  is  known  upon  so  wide  a  sion  to  guard  against  possible  criti- 
subject,  but  merely  to  say  as  much  cism.  The  reader  who  would  go 
as  was  absolutely  necessary  for  the  further  into  this  department  of  the 
proper  comprehension  of  the  sequel,  subject  will  find  full  details  in 
Hence  I  have  intentionally  omitted  Helmholtz's  "  Handbuch  der  Phy- 
whatever  might  prove  a  stumbling-  siologischen  Optik,"  and  a  very  read- 
block  to  the  general  reader,  such  able  abstract  in  Von  Bezold's  "Theory 
as  the  difference  between  absorption  of  Colour,"  translated  by  S.  R.  Koeh- 
colours  and  interference  colours,  or  ler  (Boston,  U.S.A.,  L.  Prang  k  Co., 
that  between  mixture  of  lights  and  1876). 


8  THE  COLOUR-SENSE. 

We  must  begin,  then,  by  allowing  that,  previous  to  all 
perception  of  colour  by  men  or  animals,  colour  itself 
existed  as  an  agency  in  the  external  universe.  The 
development  of  the  colour-sense  is  equivalent  to  the 
growth  of  a  mechanism  by  which  this  agency  became 
capable  of  affecting  organic  matter.  In  the  present 
chapter  we  will  consider  the  nature  of  the  objective 
agency,  while  in  the  next  we  shall  have  to  look  at  the 
first  and  rudest  form  of  the  percipient  mechanism. 

Throughout  the  whole  vast  ocean  of  space  in  which 
suns,  stars,  and  planets  float  like  inconspicuous  islets  of 
light,  modern  science  has  taught  us  that  an  all-pervading 
element,  known  as  sether,  fills  every  available  interstice. 
From  constellation  to  constellation  of  sidereal  bodies  the 
sether  spreads  in  wide  expanses,  which  stretch  uninter- 
rupted over  countless  millions  of  miles.  Between  atom 
and  atom  of  terrestrial  substances  the  sether  penetrates 
into  ti^  intervals  whose  minuteness  the  boldest  mathe- 
maticians have  only  lately  ventured  to  measure.  Where- 
ever  matter  is  not,  sether  is.  Every  sun  and  every  molecule 
floats  in  a  circumambient  matrix  of  this  unknown  accent. 
If  we  could  view  the  most  solid  body  with  a  microscopic 
eye,  magnifying  some  thousands  of  millions  of  diameters, 
we  should  see  that  it  was  composed  of  innumerable  little 
masses,  none  of  them  in  actual  contact  with  its  neighbours, 
but  all  bound  to  one  another,  as  the  earth  is  to  the  sun, 
by  their  mutual  attractions  extending  over  an  intervening 
space.  This  space  would  be  filled,  in  the  one  case  as  in 
the  other,  by  the  ubiquitous  sether.  And  though  we  can 
never  succeed  in  knowing  its  existence  directly,  yet  we 
are  every  moment  experiencing  its  effects  in  the  most 
obvious  and  unmistakable  manner.  Just  as  we  believe 
in  air,  which  we  never  see,  because  we  can  feel  it,  so  we 
believe  in  aether,  which  we  can  never  handle,  because  we 
perpetually  see  by  it  and  through  it. 

^ther,  though  infinitely  light  and  elastic,  is  naturally 
a  solid,  or  something  very  like  one.     But  it  shares  the 


^THER-WAVES  AND  THEIR  VARIETIES.         9 

common  property  of  other  solids  in  its  ability  to  transmit 
•undulations  from  a  centre  of  disturbance.  We  all  know 
that  if  we  set  any  body  in  motion,  it  imparts  a  portion  of 
its  motion  to  all  other  bodies  with  which  it  comes  in  con- 
tact. So,  too,  if  we  set  up  vibratory  movements  in  a  bell, 
we  know  that  its  particles  knock  up  against  the  air- 
particles  in  their  neighbourhood,  and  thereby  send  off  into 
surrounding  space  a  Series  of  concentric  air-waves,  which, 
when  they  strike  the  appropriate  human  organ,  are  known 
to  us  in  consciousness  as  sounds  or  tones.  And  in  exactly 
the  same  way,  when  disturbances  of  a  peculiar  kind  affect 
material  particles  of  any  sort,  they  set  up  a  like  series  of 
concentric  waves  in  the  circumambient  sether,  which, 
falling  in  turn  on  their  appropriate  organs,  are  recognised 
in  consciousness  as  heat,  light,  or  colour.  What  is  the 
exact  nature  of  these  waves  and  their  differences  we  have 
next  to  inquire. 

Apparently  every  movement  of  a  material  body  or 
particle  sets  up  more  or  less  motion  in  the  surrounding 
aether.  We  know  now  that  every  sound,  every  moving 
energy,  every  activity  of  any  sort,  as  it  dies  away,  is 
transferred  by  minute  friction  to  the  setherial  medium 
which  bathes  us  on  every  side.  But  the  stronger  class  of 
sether- waves,  with  which  we  have  now  to  deal,  is  origin- 
ated only  in  a  single  way.  They  all  arise  from  the  vibra- 
tions of  a  material  body  in  that  state  of  rapid  molecular  or 
atomic  motion  which  we  commonly  know  as  red  or  white 
heat.  The  waves  thus  set  up  may  be  reflected,  refracted, 
twisted  about,  and  returned  in  varying  proportions  by 
other  surrounding  objects,  but  they  all  owe  their  original 
existence  to  a  heated  material  mass,  whether  that  mass  be 
the  sun,  the  dog-star,  the  drawing-room  fire,  or  the  flame 
of  a  candle.  So  we  must  look  for  a  moment  at  the  source 
of  such  sether-waves  before  we  can  comprehend  the  nature 
of  the  waves  themselves. 

Directly  or  indirectly,  in  every  case,  the  vibration  of  the 
original  heated  body  is  due  to  the  rushing  together  of 


lo  THE  COLOUR-SENSE. 

masses,  molecules,  or  atoms  which  were  previously  in  a 
state  of  separation.  In  the  heavenly  bodies,  the  sun  and 
the  fixed  stars,  the  attraction  of  gravitation  (which  affects 
masses)  is  drawing  together  their  skirts;  and  under  its 
influence  the  outlying  matter  of  their  systems  is  clashing 
with  the  central  sphere  and  producing  a  terrific  degree  of 
heat ;  just  as  the  continued  clashing  of  hammers  on  an 
anvil  will  heat  a  piece  of  iron  red-hot  here  on  our  little 
earth.  In  the  grate  and  the  candle,  agrain,  the  attraction 
of  chemical  affinity  (which  affects  atoms)  is  drawing 
together  tiny  particles  of  carbon  and  oxygen ;  and  as  the 
atoms  clash  against  one  another  in  the  embers  or  the 
flame,  they  are  put  into  a  similar  state  of  rapid  vibration 
or  heat.  In  physical  language,  the  potential  energy  of 
their  previous  separation  has  become  kinetic  in  the  act 
of  union,  and  is  now  being  radiated  off  to  surrounding 
objects.  As  the  quickly  vibrating  little  bodies,  either  in 
the  sun  or  the  flame,  fly  from  side  to  side,  they  impart 
each  second  a  portion  of  their  moving  energy  to  the  aether 
about  them;  and  each  setherial  molecule  continues  to 
impart  the  communicated  impulse  to  adjacent  molecules, 
so  that  a  series  of  spherical  waves  is  set  up  in  every 
direction  from  the  central  disturbance.  If  nothing  inter- 
venes to  prevent  them,  these  waves  go  on  widening  and 
weakening  through  all  space  ad  infinitum,  at  least  as  far 
as  human  science  or  conjecture  can  follow  them. 

But  all  the  sether-waves  are  not  of  exactly  the  same 
size,  nor  do  they  follow  one  another  with  exactly  the  same 
rapidity.  When  a  material  body  vibrates  with  a  com- 
paratively slight  motion  (or,  as  we  say  in  other  words,  is 
only  slightly  heated),  the  waves  to  which  it  gives  rise  are 
comparatively  slow  and  voluminous :  as  the  rate  of  vibra- 
tion increases,  more  rapid  waves  succeed  in  the  surround- 
ing sether;  and  when  the  rapidity  of  vibration  becomes 
very  great,  the  resulting  waves  follow  one  another  with 
an  almost  incredible  speed.  Three  principal  varieties  of 
slower  or  quicker  sether-waves  are  commonly  distinguished, 


^THER-WAVES  AND  THEIR  VARIETIES.        ii 

according  to  the  effects  wliich  they  produce  upon  the 
human  org^ans. 

The  slowest  undulations  are  known  as  heat-waves ;  those 
of  intermediate  rapidity  as  light-waves ;  and  the  quickest 
of  all  as  chemical  waves. 

All  three  classes  of  waves  are  produced  together  by  a 
body  in  a  state  of  high  molecular  energy,  such  as  the  sun. 
Fortunately,  we  are  able  to  separate  the  various  kinds  from 
one  another,  and  to  demonstrate  their  several  properties, 
by  means  of  a  simple  piece  of  triangular  glass,  known  as 
a  prism. 

If  we  make  a  small  slit  in  the  shutter  of  a  darkened 
room,  and  allow  a  few  of  the  sether-waves,  generated  by 
the  sun,  to  enter  through  this  aperture,  we  can  interpose 
the  prism  across  their  path,  and  project  them  sideways  on 
to  a  screen.  When  we  do  so  we  find  that  the  various 
waves  are  all  bent  upward,  but  not  all  equally.  They 
occupy  a  broad  space  on  the  screen,  the  slowest  waves 
striking  the  lowest  portion,  and  the  quickest  falling  at  the 
top,  while  those  of  intermediate  speed  hit  the  middle 
space.i  If  we  put  a  thermometer  of  very  delicate  con- 
struction (known  as  a  thermopile)  at  the  lowest  point 
where  the  waves  surge  against  the  screen,  we  shall  find 
that,  in  this  portion  of  the  wave-bundle,  the  undulations 
possess  great  heating  power.  If  we  put  a  piece  of  speci- 
ally prepared  paper  at  the  highest  point  where  the  waves 
alight,  we  shall  similarly  find  that  the  undulations  of  that 
region  possess  high  chemical  power.  And  if  we  look  at 
the  intermediate  space,  we  shall  see  for  ourselves  that  the 
waves  of  that  part  produce  the  greatest  amount  of  light 
and  colour.  So  here  we  learn  that  in  every  bundle  of 
solar  aether-waves  these  three  classes  of  undulations  are 
closely  combined;  but  by  the  interposition  of  a  proper 
medium  they  can  be  sifted  and  separated  each  into  a 
place  of  its  own. 

1  As  my  purpose  is  here  to  explain     careful  to  avoid  any  allusion  to  the 
the  objective  nature  of  colour,  I  am    subjective  differences  of  perception. 


12  THE  COLOUR-SENSE. 

Fundamentally,  then,  light  and  radiant  heat  are  iden- 
tical. And  not  only  so,  but  a  third  order  of  rays — the 
chemical — is  always  bound  up  with  them  in  the  waves 
which  come  to  us  from  the  sun.  Yet  though  in  their 
objective  nature  these  various  agencies  are  so  similar — 
differing  not  at  all  in  kind,  but  only  in  degree — there  is 
a  very  strange  diversity  in  our  subjective  perception  of 
their  effects.  The  slowest  aether-waves  we  perceive  with 
every  portion  of  our  bodies,  and  know  as  heat ;  the  inter- 
mediate sether- waves  we  perceive  through  a  pair  of  small 
and  special  organs — the  eyes — and  know  as  light ;  while 
the  fastest  sether- waves  we  do  not  perceive  at  all,  except 
by  very  rounda.bout  and  indirect  means. 

The  reasons  for  this  difference  must  surely  be  very 
striking  ones.  It  seems  curious  that  such  similar  agen- 
cies should  be  so  diversely  cognised,  or  should  escape  our 
cognisance  altogether.  And  it  is  for  the  purpose  of  bring- 
ing into  clear  relief  so  strange  a  fact  that  I  have  chosen 
what  doubtless  seemed  at  first  sight  an  awkward  and 
unfamiliar  mode  of  envisaging  a  well-known  subject. 
The  question  why  we  have  two  distinct  methods  for  per- 
ceiving two.  closely  allied  forms  of  sether- waves,  and  no 
method  at  all  for  perceiving  the  third,  is  a  question  which 
evolutionism  is  bound  to  answer  before  it  proceeds  to  the 
minor  discrimiDation  of  those  lesser  differences  know^n  as 
colours. 

For  when  we  look  at  the  matter  objectively,  we  see  at 
once  that  each  colour  differs  from  its  neighbour  in  just  the 
same  manner  as  heat  differs  from  light,  though  only  to  a 
less  degree.  Accordingly,  we  must  ask  first,  Whj  are  the 
senses  of  animals  so  difi'erently  affected  by  the  extremes 
and  the  mean  of  the  solar  undulations  ?  And  when  we 
have  answered  that  question  we  may  go  on  to  the  next, 
How  did  the  various  minor  undulations  of  mean  rapidity 
come  to  have  differential  sensations  attached  to  them  in 
consciousness  ? 

Fortunately,  the  answer  is  not  a  very  difficult  one.     The 


^THER-WAVES  AND  THEIR  VARIETIES.        13 

slower  and  more  massive  "undulations,  which  we  know  as 
heat-waves,  produce  very  marked  results  even  upon  inor- 
ganic bodies,  while  their  effects  upon  organic  matter  are 
obvious  and  enormously  important.  To  the  animal,  cold 
is  death  and  warmth  is  life.  Hence  it  is  not  astonishing 
that  animals  should  very  early  have  developed  a  sense 
which  informed  them  of  the  changes  of  temperature  taking 
place  in  their  vicinity;  and  that  this  sense  should  have 
been  equally  diffused  over  the  whole  organism,  ^ther- 
waves  of  slow  vibration  are  capable  of  setting  up  motion 
in  the  molecules  of  all  bodies  upon  which  they  impinge, 
as  we  know  familiarly  when  we  touch  a  stone  on  the 
summer  beach,  or  grasp  a  poker  which  has  lain  long  in 
front  of  the  fire;  and  the  motion  so  absorbed  we  call 
warmth:  while,  on  the  other  hand,  molecules  in  rapid 
motion  give  up  their  energy  to  the  surrounding  aether,  as 
we  also  know  when  a  red-hot  poker  cools,  or  when  we 
expose  our  faces  to  the  chilly  wind  of  winter ;  and  the 
loss  of  motion  so  induced  we  call  cold.  In  either  case, 
the  immediate  effects  are  so  highly  important  to  animal 
life,  that  we  may  well  imagine  the  accompanying  sensa- 
tions to  be  amongst  the  earliest  which  evolution  could 
have  produced.  As  soon  as  moving  creatures  began  to 
feel  at  all,  they  j)robably  began  to  feel  heat  and  cold. 

The  sether-waves  of  middle  frequency,  however,  do  not 
produce  such  plain  and  universal  results.  If  we  interpose 
a  slab  of  rock-salt  in  the  course  of  a  solar  beam,  w^e  can 
sift  out  of  it  all  the  slower  undulations  (or  heat-waves), 
which  are  selected  and  absorbed  by  the  salt  itself.  On 
placing  oi^r  hands  in  the  path  of  the  remaining  wavelets, 
we  do  not  experience  any  feeliog  of  heat  whatsoever. 
And  if  we  put  a  piece  of  inorganic  matter — say  a  pebble 
— in  the  course  of  the  sifted  ray,  we  shall  find  that  it  is 
similarly  unaffected  in  temperature  or  structure.  The 
thermopile  conclusively  shows  us  that  little  or  no  imme- 
diate mechanical  power  is  left  in  the  wavelets  which  pass 
through  the  rock-salt.     If  we  examine  the  results  which 


14  THE  COLOUR-SENSE. 

these  middle  undulations  produce  upon  the  world  at  large, 
we  shall  arrive  at  similar  conclusions.  While  to  the  heat- 
waves are  due  the  conspicuous  differences  of  summer  and 
winter,  ice,  snow,  and  rain,  the  poles  and  the  tropics, 
besides  the  great  phenomena  of  ocean-currents,  winds, 
evaporation,  clouds,  rainfall,  and  atmospheric  disturbances 
generally ;  their  companions,  the  light-waves,  scarcely  pro- 
duce any  noticeable  effects  at  all.  Falling  upon  the  mass 
of  the  earth's  surface,  they  are  not,  like  the  slower  undula- 
tions, absorbed  and  communicated  through  the  substance 
on  which  they  impinge,  but  are  reflected  and  twisted  back 
upon  space  in  every  possible  direction.  Even  if  they  are 
partially  taken  in  by  the  matter  on  which  they  fall,  yet 
the  greater  portion  of  them  are  returned  without  effecting 
any  change  in  its  arrangement ;  and  if,  as  in  the  case  of 
what  we  call  a  black  surface,  a  large  number  or  the  whole 
of  them  are  absorbed  and  retained,  they  are  yet  degraded 
by  the  process  into  the  form  of  heat-waves,  from  which 
they  cannot  be  consciously  discriminated  except  by  in- 
direct means.  These  middle  waves  could  not,  therefore, 
prove  of  any  great  importance  to  animal  life  in  its  earliest 
days;  and  we  need  not  wonder  that  no  sense  for  their 
perception  was  at  first  developed. 

There  is  one  conspicuous  exception,  however,  to  this 
comparative  inertness  of  the  light-waves — I  mean  the 
case  of  plants.  In  their  leaves,  the  middle  and  quickest 
setherial  undulations  become  the  a^^^ents  for  efiecting;  great 
chemical  and  physical  changes,  upon  which  the  whole 
course  of  mundane  life  entirely  depends.  But  these  fat;ts, 
all-important  in  themselves,  do  not  directly  affect  our 
present  question.  Light  is  essential  to  animal  life,  because 
it  is  essential  to  the  plants  upon  which,  mediately  or  imme- 
diately, animal  life  subsists.  But  a  perception  or  discri- 
mination of  light  is  not  at  all  necessary,  except  in  a  very 
roundabout  and  derivative  way.  Why  it  has  arisen  at 
all  we  may  next  briefly  inquire. 

The  light-waves   falling  upon  a  body  do  not  largely 


^THER-WAVES  AND  THEIR  VARIETIES.        15 

affect  it,  as  a  rule,  in  any  way.  They  may  occasionally 
be  employed  in  bringing  about  slight  changes  of  its  super- 
ficial molecules,  but  they  do  not  penetrate  deeply  or 
work  conspicuous  rearrangements  of  its  whole  substance. 
Nevertheless,  the  power  of  discriminating  them  may  in- 
directly benefit  an  animal  organism.  If  a  jellyfish,  swim- 
ming at  the  water's  top,  has  eyelets  upon  which  the  in- 
cident light-waves  produce  distinct  effects,  it  may  be 
warned  of  the  approaching  enemy,  or  informed  of  passing 
prey,  by  having  the  path  of  the  aether- waves  cut  off  from 
above.  Still  more  valuable  will  the  nascent  sense  become, 
if,  instead  of  being  restricted  to  the  full  force  of  directly 
incident  undulations,  it  is  capable  of  being  impressed  by 
reflected  waves.  In  this  case,  not  only  will  the  creature 
be  conscious  of  objects  passing  between  it  and  the  source 
of  light,  but  it  will  be  able  to  receive  varying  stimulations 
from  aU  surrounding  objects  upon  which  the  light  falls. 
The  more  highly  developed  its  sight  becomes  (for  we  may 
now  use  the  language  of  ordinary  life  without  fear  of 
ambiguity),  the  more  clearly  will  it  be  affected  by  the 
beams  which  are  twisted  about  and  returned  upon  space 
from  every  neighbouring  body.  Until  at  last  that  very 
fact  in  the  light- waves  which  made  them  originally  so  un- 
important— the  fact  that  they  glance  off  every  object  they 
hit  like  a  ball  reboundinf^  from  a  wall — chives  them,  in  our 
eyes,  the  greatest  value,  by  enabling  us  to  discriminate 
from  a  distance  the  shape  and  texture  of  all  we  see,  with- 
out the  trouble  of  actual  examination  by  the  hands  and 
fingers. 

But  this  specialised  sense  is  hardly  likely  to  spread 
itself  over  the  whole  body,  like  the  sense  of  heat  and  cold. 
Not  only  should  we  derive  no  advantage  from  being  all 
eye,  but  we  should  be  positively  incommoded  rather  than 
benefited  by  such  an  arrangement.  It  will  only  be  in 
certain  special  spots  or  ocdli  that  the  perception  of  light 
will  probably  begin;  and  as  the  sense  strengthens,  we 
shall  find  these  spots  becoming  fewer  and  fewer,  until  in 


1 6  THE  COLOUR-SENSE. 

the  approximately  perfect  organisms  they  are  reduced  to 
the  two  conspicuous  orbs  which  we  commonly  call  eyes. 
All  such  questions,  however,  must  be  left  over  for  a  while, 
until  we  come  to  examine  the  development  of  the  rudi- 
mentary vision.  At  present  we  must  hurry  on  to  reach 
our  proper  subject — the  objective  nature  of  colour. 

As  for  the  third  class  of  setherial  undulations,  the 
quickest  or  chemical  waves,  their  effects  are  so  slight  and 
inconspicuous  that  we  have  never  had  occasion  to  develop 
any  sense  whatsoever  for  their  perception.  It  is  only  quite 
recently,  and  by  quite  indirect  methods  (chiefly  through 
the  investigations  of  the  earliest  photographers),  that  we 
have  come  to  recognise  their  existence  at  all.  Neither 
upon  inorganic  substances  nor  upon  animal  bodies  do 
they  produce  any  striking  result;  so  that  we  need  not 
wonder  at  our  inability  to  perceive  them,  either  with  our 
whole  organism  or  with  any  specialised  organ.  What- 
ever has  no  influence  upon  our  welfare  as  a  species 
can  never  have  any  effect  upon  the  modification  of  our 
senses. 

We  can  dimly  understand,  then,  why  these  three  kinds 
of  sether-waves,  differing  from  one  another  only  in  their 
relative  size  and  frequency,  should  be  commonly  thought 
of  as  such  utterly  unlike  agencies.  The  slowest  waves 
affect  all  material  substances  alike,  and  are  consequently 
cognised  by  our  whole  bodies  as  heat.  The  middle  waves 
are  cast  off-  in  varying  proportions  by  almost  every  sub- 
stance upon  which  they  fall,  but  possess  little  power  of 
modifying  their  arrangement,  and  are  consequently  cog- 
nised by  a  very  special  organ — the  eye  ;  while  the  quickest 
waves  are  almost  inert,  so  far  as  our  present  purpose  is 
concerned,  and  are  consequently  not  cognised  by  us  at 
all,  except  mediately  and  intellectually. 

And  now  that  we  have  seen  the  objective  nature  of 
light  in  general,  let  us  ask  what  is  the  objective  nature  of 
colours  in  particular. 

As  I  said  above,  each  colour  bears  objectively  the  same 


^THER-WAVES  AND  THEIR  VARIETIES.        17 

relation  to  light  as  light  itself,  heat,  and  chemical  rays 
bear  to  the  whole  set  of  setherial  undulations. 

If,  once  more,  we  have  recourse  to  the  prism  and  the 
darkened  room,  we  can  throw  a  bundle  of  sether- waves  as 
before  upon  a  white  screen.  Neglecting  now  the  two  ex- 
tremes, the  heat-rays  and  the  chemical  rays,  which  are  of 
course  invisible,  we  need  only  concern  ourselves  with  the 
middle  or  light-rays,  which  form  a  bright  band  of  colours, 
ranging  from  red  to  violet.  The  lowest  part  of  this  band 
or  spectrum,  next  to  the  place  where  the  thermopile 
showed  us  the  existence  of  the  heat-rays,  is  occupied  by 
red.  After  it,  in  ascending  order,  come  orange,  yellow, 
green,  and  blue  ;  while  the  highest  place,  next  to  the  point 
where  the  sensitised  paper  showed  us  the  existence  of  the 
chemical  rays,  is  filled  by  a  belt  of  violet.  Each  of  these 
colours  answers  to  a  set  of  aether- waves,  whose  frequency 
is  intermediate  between  that  of  heat-rays  and  chemical 
rays  in  the  order  just  given.  Slowest  of  all  visible  rays 
are  the  red,  next  come  the  green  and  blue,  while  the 
violet  are  the  quickest  waves  capable  of  producing  any 
direct  effect  upon  the  eye. 

In  the  case  of  such  a  solar  spectrum,  we  have  sifted  out 
the  various  orders  of  sether-waves  by  means  of  their 
varying  ref Tangibility,  that  is  to  say,  the  extent  to  which 
each  is  capable  of  being  bent  aside  from  its  direct  course 
by  means  of  the  prism.  But  there  are  other  ways  in 
which  the  same  effect  may  be  produced.  Tor  example, 
we  may  intercept  the  whole  bundle  of  compound  undula- 
tions with  a  piece  of  specially  prepared  glass,  (red  glass,  as 
we  call  it),  which  sifts  out  all  the  quicker  waves,  leaving 
only  the  red,  just  as  the  rock-salt  sifted  out  all  the  heat- 
waves. Similarly,  we  may  take  a  piece  of  green,  blue,  or 
violet  glass,  which  will  cut  off  all  but  the  proper  kind  of 
waves  which  it  is  intended  to  let  through.  Neither  of 
these  ways,  however,  is  a  common  one  in  external  nature. 
The  rainbow  shows  us  the  solar  spectrum,  and  the  green 
light  which  has  passed  through  a  stratum  of  water  gives 


1 8  THE  COLOUR-SENSE. 

lis  an  instance  of  selective  absorption;  but  tbe  way  in 
which  ordinary  colour  is  produced  is  a  slightly  different 
one. 

We  saw  above  that  every  sether-wave  has  its  origin  in 
an  incandescent  body,  celestial  or  mundane.  But  most  of 
the  objects  which  we  see  every  day  are  not  tjiemselves 
incandescent;  the  light  by  which  we  perceive  them  is 
reflected  from  the  sun.  Now  when  the  light-waves  from 
the  sun  strike  upon  any  terrestrial  object,  they  may  be 
reflected  in  a  great  many  different  manners.  If  the  sur- 
face upon  which  they  fall  is  perfectly  smooth  and  quit^ 
opaque  (or  incapable  of  transmitting  the  undulations 
through  its  substance),  the  waves  will  be  returned  in  their 
entirety,^  as  when  we  see  an  image  of  the  sun  in  a  mirror. 
Here  the  waves  are  sent  back  as  they  came,  exactly  in 
the  same  way  as  when  a  ball  rebounds  from  the  wall.  If, 
however,  the  surface  is  not  quite  smooth,  but  yet  has 
no  special  selective  power  for  any  one  set  of  waves  rather 
than  another,  the  light  is  then  returned,  not  directly  as  it 
came,  but  dispersedly  in  every  direction.  Such  an  object 
is  said  to  be  white,  and  its  mode  of  treating  the  light  may 
be  compared  to  the  case  of  a  stone  thrown  against  a  wall, 
and  shivered  in  every  direction  into  a  thousand  pieces. 
Again,  if  the  surface  has  such  a  molecular  disposition  that 
it  absorbs  or  neutralises  one  or  more  sets  of  waves,  and 
only  returns  one  or  more  other  sets,  then  it  is  said  to  be 
coloured.  If  it  absorbs  all  the  green,  blue,  and  violet 
rays,  returning  only  the  red,  then  it  is  said  to  be  a  red 
object,  because  the  red  rays  alone  strike  our  eyes  when  we 
look  at  it.  Similarly,  if  it  absorbs  all  the  red,  orange,  and 
violet  rays,  returning  only  the  green,  it  is  said  to  be  a 
green  object.  And  so  on  throughout.  Lastly,  if  it  absorbs 
all  the  ?ether- waves,  degrading  their  light  into  the  form  of 
heat,  and  returning  none,  it  is  said  to  be  black.^ 

1 1  am  speaking  broadly,  and  pur-  will  forgive  me  for  simplifying  the 

posely  neglect    minute   and  tedious  question  by  omitting  all  reference  to 

details.  inner     reflexion    and    other    minor 

^  I  trust  the  critical  scientific  reader  points. 


JETHER-WAVES  AND  THEIR   VARIETIES.         19 

Almost  every  object  upon  which  the  sunlight  falls 
possesses  a  power  of  selecting  and  returning  various 
aether- waves  in  varying  proportions.  Were  it  not  so,  the 
sense  of  sight  could  never  have  been  developed.  If  all 
objects  alike  absorbed  all  the  rays  which  fell  upon  them, 
then  the  .whole  earth  would  be  one  unbroken  sheet  of 
black,  and  the  only  visible  things  would  be  the  sun  and 
the  fixed  stars.  If  all  objects  alike  reflected  all  the  rays 
which  fell  upon  them,  then  the  whole  earth  would  be  one 
mass  of  dazzling  white,  without  distinction  of  shape  or 
colour.  But  as  each  object  reflects  and  disperses  the  light 
in  different  ways  from  every  point  of  its  surface,  the 
discrimination  of  form,  of  light  and  shade,  and  of  colour 
becomes  possible.  The  existence  of  the  two  first-named 
faculties  we  must  take  for  granted  in  this  work,  though 
we  shall  have  somewhat  further  to  say  about  them  in  the 
succeeding  chapter.  But  the  discrimination  of  colour, 
the  proper  subject  of  our  treatise,  demands  a  little  more 
detailed  treatment  even  at  this  preliminary  stage. 

By  colour-perception,  then,  we  shall  understand  in  the 
present  work  the  power  of  discriminating  hetiveen  light- 
ivaves  having  different  rates  of  frequency.  If  any  creature 
shows  by  its  actions  that  it  is  endowed  with  such  a  power, 
we  shall  say  that  it  possesses  a  colour- sense.  Anything 
more  than  this  it  is  impossible  to  prove.  Whether  the 
sensation  or  mental  idea  hhte,  as  perceived  or  thought  by 
a  butterfly  or  a  humming-bird,  is  the  same  in  conscious- 
ness with  the  sensation  or  mental  idea  hlue  as  perceived 
or  thought  by  you  and  me,  we  can  never  know.  For, 
observe,  we  can  never  even  know,  shifted  with  lan^^ua^e 
as  you  and  I  are,  whether  my  perception  of  blue  is  the 
same  as  yours;  far  less  then  can  we  know  this  same 
thing  in  the  case  of  animals  whose  minds  are  so  widely 
diverse  as  man's  and  the  butterfly's,  and  between  whom 
intercommunication  is  impossible.  But  we  can  know  by 
means  of  language  that  certain  objective  differences  which 
differentially  affect  me  also  differentially  affect  you.    And 


20  THE  COLOUR-SENSE. 

so  too  we  can  know,  by  the  testimony  of  voluntary  or  auto- 
matic action,  tliat  these  same  objective  differences  which 
differentially  affect  us  two,  in  like  manner  differentially 
affect  birds,  fishes,  and  insects.  Such  a  power  of  being 
differentially  affected  in  the  particular  case  of  medium 
sether-waves  having  quicker  or  slower  rates  of  recurrence, 
we  call  the  colour-sense. 

Moreover,  just  as,  in  spite  of  this  logical  and  meta- 
physical difticulty,  no  two  human  beings  ever  seriously 
and  really  doubted  the  practical  and  essential  identity  of 
their  respective  sensations,  so  too  in  the  case  before  us, 
I  think  we  shall  find  such  a  general  agreement  in  the 
likes  and  dislikes  of  taste,  smell,  sound,  and  colour, 
running  through  tw^o  large  groups  of  animals,  whose 
general  habits  of  life  coincide  in  the  main,  that  we  shall 
not  hesitate  practically  to  assert  the  correspondence  of 
OUT  idea  of  colour  with  that  of  beasts,  birds,  fishes,  and 
insects.  That  we  can  'prove  this  correspondence  no  one 
could  for  a  moment  maintain ;  but  that  we  should  believe 
it  without  strict  proof,  is  not,  it  seems  to  me,  a  very 
dangerous  precedent.  Eather  should  we  hesitate  to 
introduce  into  our  conception  of  the  uniform  order  of 
nature  any  supposed  difference  in  kind  without  full  and 
weighty  reason. 

A  few  words  more,  before  we  close  this  unavoidably 
tedious  preliminary  statement,  as  to  the  nature  of  the 
colours  objectively  existent  in  nature.  As  a  rule,  the 
bundles  of  sether- waves  which  fall  upon  terrestrial  objects 
are  not  directly  reflected  (in  other  words,  the  world  is  not 
made  up  of  innumerable  mirrors) ;  nor  are  they  dispersed 
in  their  integrity  (in  other  words,  the  world  is  not  a  sheet 
of  snowy  white) ;  nor  are  they  all  wholly  absorbed  (in 
other  words,  the  world  is  not  a  pall  of  sombre  black).  A 
few  objects  have  sijch  surfaces  as  to  reflect  totally,  like 
looking-glasses,  mercury,  or  calm  water;  a  few  others 
have  such  a  molecular  constitution  as  to  disperse  the 
total  beam,  like  snow-white  paper  and  bleached  linen ;  a 


jETHER-VVAVES  AND  THEIR  VARIETIES.         21 

few  more  have  such  a  different  molecular  arrangement  as 
to  absorb  entirely,  like  soot,  lampblack,  and  broadcloth. 
But  most  bodies  have  their  molecules  so  set  as  to  absorb 
certain  amounts  or  orders  of  gether- waves  and  to  return, 
certain  other  amounts  or  orders.  It  is  these  last  of  which 
we  generally  speak  as  coloured  objects. 

Practically  speaking,  black,  white,  and  grey  only  diffej? 
in  the  amount  of  waves  which  they  reflect  and  absorb,  not 
in  their  kinds.  A  black  object  absorbs  nearly  all ;  a  white 
object  disperses  nearly  all ;  a  grey  object  absorbs  some  and 
disperses  some,  but  in  nearly  equal  proportions  of  the 
various  kinds.  These  varieties,  then,  yield  us  no  sensa- 
tions of  colour  proper,  but  rather  of  light  and  shade. 

But  many  objects — the  vast  majority  of  objects,  in 
fact — do  not  reflect  the  various  constituents  of  the  total 
wave-bundle  in  their  entirety  or  in  equal  proportions. 
They  have  such  a  molecular  constitution  that  they  select 
from  the  waves  which  fall  upon  them  certain  special 
waves,  whose  frequency  is  the  same  as  their  own  natural 
rate  of  oscillation,  or  else  a  multiple  of  the  same.  All 
others  they  reject  and  reflect  back  upon  the  aether  with- 
out. It  is  these  reflected  waves  which  fall  upon  our  eyes 
and  yield  us  the  sensation  of  colour. 

Very  few  natural  objects,  again,  outside  the  organic 
class,  yield  us  pure  colours.  Most  of  them  are  of  dull 
mixed  hues,  like  the  various  earths,  sands,  rocks,  and 
clays.  A  very  small  and  highly  prized  class  of  inorganic 
bodies  do,  indeed,  reflect  light  of  a  single  sort  only,  as  in 
the  ruby,  the  topaz,  the  amethyst,  and  other  precious 
stones.  But,  as  a  rule,  inorganic  bodies,  as  found  in 
nature,  are  dull  browns,  dingy  greys,  or  muddy  whites. 
When  we  turn  to  the  organic  world,  however,  we  find 
pure  colours — that  is  to  say,  aether-waves  of  single  or 
slightly  compounded  orders — very  prevalent.  In  the  green 
leaves  of  trees,  the  brilliant  tints  of  flowers,  the  lovely 
hues  of  fruits,  the  wings  of  butterflies,  the  feathers  of 
birds,  we  find  colour  constantly  appearing  in  very  pure 


22  THE  COLOUR-SENSE. 

forms.  We  shall  see  reason  in  the  sequel  to  conclude 
that  these  pure  waves,  rather  than  the  mixed  and  con- 
fused systems  of  inorganic  nature,  have  given  rise  to  the 
perception  of  colour  in  animal  organisms. 

And  now  let  me  briefly  sum  up  the  points  which  I 
have  been  endeavouring  to  italicise  in  this  preamble. 
Colour,  objectively  viewed,  is  nothing  more  or  less  than 
the  different  rate  of  oscillation  in  different  sether-waves. 
The  colour-sense,  subjectively  viewed,  is  an  exaggerated 
difference  of  perception  attached  to  the  effects  of  these 
external  agencies,  which  really  differ  so  very  little  between 
themselves.  And  the  problem  of  its  origin  is  this — How 
did  these  slight  differences  in  the  frequencies  of  sether- 
waves  reflected  from  various  organic  or  inorganic  bodies 
come  to  have  such  disproportionately  diverse  sensations 
attached  to  them  in  consciousness  ?  In  other  words, 
when  red  light  differs  from  blue  light  only  in  degree,  why 
does  red  differ  from  blue,  as  we  know  them,  in  kind  ? 

The  questions  thus  proposed  our  future  chapters  must 
endeavour  to  answer. 


(      23      ) 


CHAPTER  III. 

THE   ORGAN   OF  VISION. 

The  perception  of  light  is  not  equally  valuable  to  all 
classes  of  animals.  It  seems  to  be  specially  connected 
with  the  power  of  locomotion.  Sessile  or  sedentary  ani- 
mals, as  a  rule,  do  not  possess  any  form  of  visual  organ ; 
while  very  free  and  active  animals,  even  of  lower  organisa- 
tion, have  well-marked  eyes.  The  Echinodermata,  for 
example,  are  far  more  highly  evolved  creatures  than  the 
Medusae,  but  their  habits  are  comparatively  sluggish, 
while  the  Medusae  lead  a  wandering,  predatory  life ;  and 
we  find  that  the  former  class  are  apparently  quite  eyeless, 
while  the  latter  have  distinct  ocelli,  which  in  some  cases 
reach  a  considerable  complexity  of  structure. 

Still  more  clearly  is  this  connection  made  evident  by 
the  metamorphoses  of  many  creatures  which  pass  from  a 
free  to  a  fixed  state.  The  young  barnacles  and  halani  are 
active,  locomotive  animals,  furnished  with  eyes,  antennae, 
and  limbs ;  but  after  a  period  of  activity,  they  finally  fix 
themselves  upon  some  solid  object,  and  undergo  a  loss  of 
all  their  higher  sense-organs.  Similar  changes  take  place 
among  the  parasitic  Entomostraca,  the  Tubicolar  Annelids, 
and  many  Mollusca.  These  must  be  regarded  as  cases  of 
degradation  or  retrogressive  development. 

Conversely,  the  Medusae  are  shown,  by  their  peculiar 
mode  of  development,  to  be  the  descendants  of  hydraform 
polypes.  During  their  sessile  stage,  when  they  exactly 
resemble  the  true  Hydroida,  they  are  as  destitute  of  eyes 
as  the  other  members  of   that  order.      But  when  they 


24  THE  COLOUR-SENSE. 

acquire  their  tentacles  and  assume  the  free  mode  of  life, 
the  ocdli  are  produced  together  with  the  other  mature 
organs.  This  must  be  regarded  as  a  case  of  progressive 
development. 

If  we  examine  the  various  classes  of  animals  in  order, 
the  same  general  connection  between  free  locomotion  and 
vision  will  be  forced  upon  us  once  more.  Passing  over 
the  Protozoa,  which  of  course  are  too  humble  in  structure 
to  exhibit  any  such  complex  nervous  organs  as  eyes,  and 
beginning  with  the  Eadiata,  we  see  that  the  only  class  in 
that  division  which  possesses  high  powers  of  locomotion 
is  the  Discophora,  or  jellyfish,  and  this  is  also  the  only 
class  provided  with  visual  organs.  Among  the  ISTemato- 
phora  or  Echinodermata,  which  are  all  very  sedentary 
animals,  eyes  are  doubtfully  present.  The  lower  vermi- 
form Articulata  are  mostly  entozoic,  and  these  of  course 
are  quite  blind  ;  but  the  few  species  which  swim  freely  in 
water  by  means  of  cilia  have  eyes  with  distinct  lenses. 
The  free  leeches  have  a  ring  of  eyes  around  the  sucking 
disc.  The  highest  of  these  vermiform  creatures — the 
Nereidse,  Peripatidse,  and  Polyophthalmidse — are  all  very 
locomotive,  and  all  have  very  highly  developed  organs  of 
vision.  So  likewise  have  the  active  little  Ptotifera.  The 
Arthropoda,  or  true  articulates,  yield  like  results.  Thus, 
among  the  Crustacea,  the  Cirrhopoda  in  their  fixed  state 
and  the  parasitic  Entomostraca  are  sightless ;  but  all  the 
higher  free  crustaceans  are  provided  with  eyes,  which  in 
the  active  crab  and  lobster  orders  attain  a  high  degree  of 
perfection.  The  flying  insects  show  us  eyes  of  great  com- 
plexity, inferior  only  to  the  same  organs  in  vertebrates,  if 
even  to  those.  Yet  while  most  of  the  Hymenoptera  (in- 
cluding the  wasps  and  bees)  have  very  acute  vision,  it  is 
noteworthy  that  the  ants,  which  have  practically  lost  their 
wings,  are  almost,  and  in  some  species  quite,  blind.  It  is 
also  a  remarkable  fact  that  the  male  and  female  ants 
which  are  winged  possess  three  ocdli,  wanting  in  the 
wingless  neuters.     Among  the  Mollusca,  in  like  manner, 


THE  ORGAN  OF  VISION.  25 

the  lower  molluscoid  animals,  most  of  which  are  fixed, 
have  no  organs  of  vision  whatsoever;  the  bivalve  mol- 
lusks,  leading  very  sedentary  lives,  are  provided  only  with 
doubtful  ocelli ;  the  relatively  active  univalves  have  true 
eyes,  but  of  low  organisation ;  while  the  free-swimming 
Cephalopods  (cuttlefish  and  their  allies)  have  eyes  as 
highly  developed  as  those  of  many  fishes.  Lastly,  the 
vertebrates,  the  most  active  division  of  any,  show  us  the 
highest  visual  organs  of  all. 

We  shall  have  reason  similarly  to  conclude  hereafter 
that  the  colour-sense,  the  most  advanced  mode  of  vision, 
is  specially  strong  amongst  the  flying  insects,  the  fishes 
(marine  analogues  of  flying  creatures),  the  birds,  and  the 
very  active  forestine  mammals.  Its  high  development  in 
these  classes  is  shown  as  well  by  the  part  they  have  borne 
in  the  evolution  of  fruits,  flowers,  and  coloured  organisms, 
as  by  their  own  brilliant  hues,  the  probable  result  of 
sexual  selection. 

Such  a  general  connection  between  locomotion  and 
vision  is  exactly  what  we  should  have  expected  from  the 
nature  of  the  case.  A  sessile  animal,  lying  in  wait  for  its 
food,  can  derive  little  or  no  benefit  from  the  possession  of 
visual  organs.  Even  if  it  could  see  the  approaching  prey 
or  the  nearing  enemy,  the  knowledge  of  their  vicinity 
would  be  useless  without  the  power  of  locomotion,  whereby 
it  might  seize  the  one  or  avoid  the  other.  Accordingly, 
most  sessile  animals  are  provided  with  very  different 
organs  for  the  prehension  of  food,  and  very  different  means 
for  withdrawal  from  threateninfr  danojer.  Some  of  them 
possess  long  floating  arms  or  tentacles,  spread  out  in  every 
direction  to  catch  the  passing  prey,  which  they  cannot 
possibly  secure  unless  it  actually  come  within  reach  of 
their  grasp.  These  for  the  most  part  withdraw  themselves 
from  attack  into  a  solid  tube,  as  in  the  case  of  the  Sertu- 
laridse,  the  Tubicolar  Annelids,  the  Balani,  and  the  Bryozoa; 
or  else  curl  themselves  up  into  a  contracted  mass,  as  in 
the  Hydra,  Sea-anemones,  Crinoidea,  and  Eotifera.    Others, 


26  THE  COLOUR-SENSE, 

again,  like  the  bivalve  MoUusca,  are  enclosed  for  protec- 
tion in  stout  shells,  and  obtain  their  food  by  the  creation 
of  currents  in  the  surrounding  water.  A  second  group, 
that  of  the  Entozoa,  live  in  the  interior  of  larger  animals, 
often  shut  off  from  the  access  of  light,  and  bathed  by  the 
nutritive  fluid  of  their  hosts.  These,  also,  apparently  find 
the  possession  of  eyes  no  benefit  to  them.  Accordingly, 
animals  originally  leading  a  life  of  either  sort  here  de- 
scribed— sessile  or  parasitic — seldom  or  never  acquire  the 
power  of  vision ;  while  animals  originally  possessing  that 
power,  which  afterwards  adopt  either  of  these  modes  of 
life,  usually  or  invariably  lose  their  eyes,  and  become 
degraded  in  many  other  ways,  in  accordance  with  the  Law 
of  Parsimony,  whereby  all  unnecessary  organs  become  gra- 
dually obsolescent. 

On  the  other  hand,  any  animal  which  has  acquired 
freedom  of  motion  will  naturally  derive  great  advantage 
from  any  premonition  of  food  or  enemies  in  his  neighbour- 
hood. Such  indications  will  enable  him  to  rush  upon  the 
former  or  to  dart  away  from  the  latter.  There  are  various 
modes  by  which  information  of  the  sort  may  be  given,  as 
by  those  material  particles  which  arouse  the  sense  of 
smell,  or  those  undulations  of  the  atmospheric  or  aqueous 
medium  which  awaken  the  sense  of  hearing ;  but  the  waves 
of  sether  described  in  the  last  chapter  form  by  far  the  most 
certain  premonition  of  all  approaching  or  neighbouring 
objects,  and  their  reactions  finally  result  in  the  sense  of 
sisjht.  Of  course  such  a  sense  cannot  arise  amon^^st 
animals  which  live  perpetually  in  the  dark,  like  the  cestoid 
and  nematoid  worms,  the  lob-worm,  and  the  common 
earth-worm,  all  of  whose  freer  relatives  are  provided  with 
more  or  less  perfect  eyes ;  and  even  those  animals  which 
originally  possessed  visual  organs  lose  them  partially  or 
entirely  under  like  circumstances,  as  we  see  in  the  Bopy- 
ridse,  Acarina,  and  many  other  parasites,  the  blind  moles, 
and  the  well-known  sightless  fish  and  reptiles  of  the  Ken- 
tucky and  Carinthian  caverns.     Similarly,  most  very  deep- 


THE  ORGAN  OF  VISION.  27 

sea  organisms  are  blind,  though  some  remarkable  excep- 
tions occur.  But  amongst  all  the  higher  free  locomotive 
and  open-air  or  shoal-water  animals  we  find  some  form  of 
mechanism  for  the  perception  of  light-waves,  developed  in 
rough  proportion  to  the  perfection  of  the  motor  system. 

There  is  good  reason  to  believe  that  such  a  mechanism 
has  been  independently  evolved,  time  after  time,  by 
several  distinct  leading  orders  in  all  the  great  classes  of 
animals.  The  eye  of  the  bee,  of  the  cuttlefish,  and  of  the 
eagle,  have  each  apparently  been  separately  developed 
from  unlike  remote  sightless  ancestors.  Accordingly,  the 
diversity  of  structure  among  these  organs  is  so  great,  that 
it  would  obviously  be  impossible  to  give  even  a  brief 
account  of  their  leading  morphological  peculiarities  in  a 
single  introductory  chapter.  It  must  sufBce  here  to  trace 
out  a  few  of  the  main  steps  in  the  evolution  of  such 
organs,  from  the  strictly  psychological  point  of  view. 

Simple  undifferentiated  animal  tissue,  such  as  we  see 
in  the  Ehizopoda,  is  probably  more  or  less  affected  by 
incident  sether-waves,  like  many  other  organic  and  inor- 
ganic substances.  But  in  order  to  produce  even  the  most 
vague  and  indeterminate  sensation  of  light — or  rather, 
sensation  having  light  for  its  exciting  cause,  since  the  sen- 
sation itself  (if  any)  is  probably  quite  indefinite  in  quality 
— certain  portions  of  the  external  coat  must  apparently 
be  specialised  by  the  collection  of  a  relatively  large 
amount  of  matter  unusually  sensitive  to  light,  and 
directly  connected  with  some  simple  or  complex  nervous 
centre.  Such  spots  are  always  marked  by  the  presence  of 
pigmentary  substances,  which  seem  to  play  an  important 
part  in  the  function  of  sight.  The  simplest  form  in  which 
they  occur  is  that  of  the  ocelli  among  naked-eyed  Me- 
dusse.^  These  consist  of  small  masses  of  pigment  cells, 
surrounding   a   minute   silicious   crystal;    and  they   are 

1  Certain  more  rudimentary  ocdli  are  apparently  degraded  forms  of 
may  perhaps  be  found  amongst  the  higher  organs,  they  may  be  left  out 
Mollusca  and  elsewhere,  but  as  these    of  consideration  here. 


28  THE  COLOUR-SENSE. 

iisiially  placed  on  the  under  edge  of  the  umbrella-like 
disc.  It  may  almost  be  doubted  whether  we  can  fairly 
attach  the  idea  of  sensation  in  any  form  to  these  very 
simple  animals ;  but  at  any  rate,  we  now  know  with  cer- 
tainty that  the  ocdli  are  organs  acted  upon  by  light,  and 
responsive  to  its  stimulation.  Mr.  G.  J.  Eomanes,  how- 
ever, the  latest  investigator  of  the  subject,  believes  that 
the  eyes  of  Medusae  are  the  simplest  possible,  because  the 
interval  between  the  stimulus  and  the  response  is  so 
relatively  great  that,  were  it  any  greater,  the  animal  could 
hardly  derive  any  advantage  from  the  organs. 

In  such  very  rudimentary  eyes,  the  only  perception  (or 
affection)  possible  is  that  of  light  or  its  negation,  the 
latter  being  probably  the  most  important.  We  may  per- 
haps dimly  figure  to  ourselves  its  nature  by  shutting  our 
eyes  and  then  passing  one  hand  between  them  and  the 
light.  Some  such  vague  consciousness  (if  any)  of  a 
change  in  the  environment,  is  doubtless  the  utmost  con- 
jectural limit  of  discophorous  vision. 

The  first  step  in  progressive  development  from  this 
earliest  form  of_yisual  organ  would  consist  in  a  simple 
increase  in  the  power  of  distinguishing  light  from  dark- 
ness. This  step  appears  to  be  the  principal  one  taken  by 
the  ordinary  univalve  MoUusca  (Gasteropoda),  whose  eyes 
probably  only  inform  them  of  such  wide  distinctions. 

But  an  eye,  to  be  of  any  special  use,  must  also  give 
more  definite  and  particular  information  with  regard  to 
surrounding  objects,  and  this  information  can  best  be  com- 
municated by  some  mechanism  for  the  perception  of  form. 
A  single  percipient  organ,  every  part  of  which  is  simul- 
taneously and  equally  affected,  cannot  afford  indications 
of  such  a  sort.  In  order  to  obtain  definite  information  as 
to  the  shape  and  disposition  of  neighbouring  bodies,  we 
must  have  a  number  of  separate  sensitive  elements,  each 
directed  towards  a  point  in  the  environing  space,  and  sub- 
tending a  greater  or  less  angle.  Every  one  of  these  ele- 
ments must  be  provided  with  a  nerve-fibre  of  its  own,  and 


THE  ORGAN  OF  VISION.  29 

connected  with  some  percipient  centre.  The  minuteness 
of  discrimination  must  depend  upon  the  number  of  such 
sensitive  elements  and  the  angles  which  they  respectively 
subtend. 

To  trace  out  in  detail  the  gradual  steps  by  which  such 
structures  were  evolved  would  be  both  tedious  and  diffi- 
cult, though  certain  materials  exist  for  the  purpose  in  the 
simple  and  compound  eyes  of  insects  and  their  larvae,  and 
in  the  eyes  of  some  lower  vertebrates.  But  it  will  suffice 
for  our  present  object  to  describe,  in  rough  generalisations, 
the  means  adopted  for  the  purpose  in  the  most  perfect 
eyes,  such  as  those  of  bees  or  of  mammals.  Here  a  large 
number  of  separate  nerve-terminals  are  arranged  in  a 
more  or  less  semicircular  form,  with  single  or  numerous 
lenses,  which  cast  the  aether-waves  upon  their  percipient 
surfaces.  Each  such  terminal  answers  to  a  separate  point 
in  the  visual  field,  and  the  mechanism  of  the  lens  is  so 
arranged  that  sether-waves  from  that  point  alone  fall 
directly  on  its  focal  surface.  Thus  every  point  in  the 
visual  field  is  represented  to  the  mind  by  an  excitation  of 
the  corresponding  terminal ;  and  the  number  and  position 
of  the  terminals  affected  gives  the  animal  a  clue  to  the 
shape  and  place  of  tlie  object.  The  interpretation  of  these 
visual  symbols  into  tactual  and  muscular  terms  becomes 
apparently  automatic  or  instinctive  in  many  cases. 

In  the  human  eye,  which  may  be  taken  as  a  fair 
specimen  of  that  found  among  mammals  generally,  the 
main  portions  of  the  mechanism  may  be  thus  briefly 
summarised.  The  external  or  optical-instrument  portion 
consists  of  a  viscid  lens,  whose  shape  and  focus  may  be 
altered  by  muscular  contraction,  so  as  to  converge  at  will 
aether- waves  from  different  sources  at  varying  distances 
upon  a  given  point  behind  it.  The  internal  or  nervous 
and  percipient  portion  consists  of  the  retina,  essentially  a 
network  of  nerve-terminals,  belonging  to  two  different 
orders,  known  as  rods  and  cones.  The  excitation,  in  vary- 
ing degrees,  of  these  terminals,  gives  rise  to  the  perception 


30  THE  COLOUR-SENSE. 

of  the  visual  field.  When  no  j^art  is  excited,  we  get  the 
blank  form  of  visual  consciousness  known  as  darkness. 
"When  the  whole  is  feebly  excited,  as  through  the  eyelids, 
we  get  a  faint  general  consciousness  of  light.  When  the 
whole  is  excited  in  the  normal  manner,  the  eyes  being 
open  and  turned  toward  an  illuminated  held,  we  get  a 
consciousness  of  mingled  light  and  shade,  yielding  us 
indications  of  form.  Those  parts  of  the  visual  field 
which  reflect  large  quantities  of  sether-waves  yield  us 
the  sensation  of  relative  light ;  those  parts  which  re- 
flect small  quantities  yield  us  the  sensation  of  relative 
_shade. 

Were  an  eye  so  constituted  to  possess  no  further  powers, 
the  whole  visual  field  would  appear  to  it  monochromatic, 
or  rather  strictly  achromatic,  and  all  objects  would  look  as 
we  see  them  in  a  stereoscopic  picture.  But  -the  human 
eye  is  also  capable  of  distinguishing  the  quality  of  light  as 
well  as  its  intensity.  Not  only  can  we  discriminate  be- 
tween black,  white,  and  grey,  between  much  and  little 
illumination,  but  we  can  also  discriminate  between  red, 
blue,  yellow,  and  green,  between  aether- waves  of  greater 
or  less  frequency.  This  last  mode  of  perception — the 
colour-sense — is  the  only  one  with  which  we  are  concerned) 
in  the  present  volume ;  and  we  shall  therefore  leave  aside 
all  other  questions  of  visual  development  as  foreign  to  our 
purpose.  Moreover,  as  our  point  of  view  is  psychological 
rather  than  physiological  or  anatomical,  we  shall  regard 
the  problem  of  its  origin  solely  from  the  mental  side, 
without  inquiring  into  the  nature  of  the  mechanism  em- 
ployed or  the  functions  of  its  various  parts. 

Any  other  method  of  inquiry  would  at  present  be  pre- 
mature. Even  in  the  human  eye,  where  the  existence  of 
a  colour-sense  is  certain,  we  know  little  or  nothing  about 
the  mode  of  its  production.  There  are  good  reasons,  it  is 
true,  for  suspecting  that  colour-perception  is  the  special 
function  of  the  cones,  while  the  discrimination  of  light  and 
shade  is  set  down  to  the  rods ;  both  because  we  find  colour- 


THE  ORGAN  OF  VISION.  31 

perception  most  pronounced  in  those  parts  of  the  retina 
where  the  cones  are  most  thickly  massed,  near  the  central 
point,  and  less  active  in  those  parts  where  they  are  rela- 
tively few,  near  the  periphery;^  and  because  the  cones 
are  wholly  wanting  in  the  eyes  of  nocturnal  animals, 
which  only  require  to  distinguish  between  light  and  shade. 
But  the  physiology  of  the  cones  is  much  disputed,  and  the 
accepted  theories  can  only  be  regarded  as  provisional. 
Moreover,  in  insects,  where  the  colour-sense  is  most  cer- 
tain after  the  human  species,  we  have  not  even  a  conjec- 
tural hypothesis  of  the  mode  in  which  it  acts. 

It  may,  however,  be  worth  while,  before  we  pass  on  to 
our  proper  subject — the  origin  and  development  of  the 
colour-sense, — briefly  to  state  the  current  theory  as  to 
the  mechanism  for  the  perception  of  colour  in  mankind. 
This  theory,  first  proposed  by  Young,  and  adopted  by 
Helmholtz  and  Schultze,  supposes  that  each  spot  on  the 
retina  contains  a  number  of  nerve-terminals,  each  of 
which  is  capable  of  excitation  by  one  colour  only,  or,  in 
other  words,  by  aether- waves  having  a  determinate  rate  of 
rapidity,  and  no  others.  By  these  terminals,  a  compound 
aether-wave  would  be  decomposed  into  its  constituent 
elements,  which  would  arouse  sensation  in  the  correspond- 
ing nerve-fibres.  It  is  usual  to  assume  three  such  primary 
percipient  elements,  adapted  respectively  to  the  stimula- 
tion of  red,  green,  and  violet  light.  All  other  colours 
would  be  represented  in  consciousness  by  combinations  of 
these  in  varying  degrees  of  intensity.  It  is  probable, 
however,  that  the  real  number  of  separate  kinds  of  terminal 
is  vastly  greater.  Moreover,  considerable  doubt  hangs 
over  the  mode  of  excitation  in  the  cones  themselves,  each 
of  which  is  supplied  with  a  large  number  of  ultimate 
nerve-fibres  (axis  cylinders),  and  is  therefore  in  all  pro- 


1  See  papers  by  Dr.   Aug.    Char-  p.  924;   and  by  Landolt  and   Char- 

pentier,  "  De  la  Vision  avec  les  Dif-  pentier,  Ooraptes  Rendus,  i8th  Feb- 

ferentes  Parties  de   la  Retine,"  in  ruary  1878,  p.  495. 
Archives  de  Physiologic,  No.  6,  1877, 


32  THE  COLOUR-SENSE. 

bability  a  compound,  not  a  simple,  percipient  element. 
It  has  lately  been  suggested  that  each  cone  may  be  pro- 
vided with  separate  portions  for  the  perception  of  the 
various  elementary  colours;  and  these  portions  may  be 
divided  either  longitudinally  or  transversely.  But  the 
whole  subject  is  still  wrapped  in  the  greatest  obscurity, 
viewed  from  the  physiological  side;  and  it  is  only  by 
approaching  it  psychologically  that  we  can  hope  to  arrive 
for  the  present  at  any  decisive  result. 


(     33     ) 


CHAPTER    IV. 

INSECTS   AND   FLOWERS. 

Now  that  we  have  examined  a  few  amongst  the  various 
modes  by  which  waves  of  aether,  as  a  whole,  may  affect  the 
sensory  system  of  animals,  let  us  turn  at  last  to  our  more 
proper  subject,  and  inquire  by  what  steps  the  different 
kinds  of  sether-waves  came  to  be  differentially  cognised 
in  consciousness  as  red,  green,  yell.ow,  or  blue.  We  find 
ourselves  now  face  to  face  with  the  ultimate  problem 
which  we  have  determined,  if  possible,  to  solve  in  the 
present  vol-ume.  We  must  see  what  immediate  advantage 
animals  could  gain  from  the  possession  of  a  nervous 
structure  capable  of  that  differential  stimulation  by  the 
diverse  varieties  of  light  which  we  know  subjectively  as 
the  colour-sense. 

There  are  two  f^reat  classes  of  animals  amoncjst  which 
the  existence  of  a  colour-sense  is  most  certain,  and  its 
reactions  upon  the  external  world  most  conspicuous. 
These  are  the  articulates  and  the  vertebrates.  The  first 
class  affords  us  the  beautiful  butterflies,  beetles,  and 
crustaceans ;  the  second  gives  us  the  golden  coats  of  fish 
and  lizards,  the  exquisite  plumage  of  tropical  birds,  and 
the  striped  or  dappled  skins  of  the  fur-bearing  mammals. 
To  the  first  we  owe  the  existence  of  flowers,  to  the  second 
we  must  refer  the  colours  of  all  bright-hued  seeds  and 
fruits.  Accordingly,  for  every  practical  purpose,  we  may 
narrow  down  our  inquiry  to  the  consideration  of  these  two 
great  classes;  and  amongst  the  articulates,  the  division 
which  most  obviously  calls  for  special  notice  is  that  of 

c 


34  THE  COLOUR-SENSE, 

insects.  So  our  first  task  must  be  to  account  for  tlie 
existence  of  a  colour-sense  in  the  insect  eye,  and  to 
discover  what  were  the  objects  for  the  sake  of  which  this 
mode  of  perception  was  developed  ? 

Clearly  the  inorganic  world  does  not  offer  us  any  chance 
of  a  satisfactory  solution.  The  dull  clay  and  grey-blue 
rocks  have  none  of  the  brilliancy  and  purity  which  is 
needed  as  the  groundwork  for  a  first  differential  stimula- 
tion. Such  complex  wave-systems  as  they  reflect  would 
be  too  mixed,  too  confused,  too  indefinite,  too  variable  to 
afford  any  means  of  clear  recognition  by  an  early  half- 
developed  sense.  And  even  if  it  were  otherwise,  the 
insect  does  not  need  to  trouble  itself  about  the  chemical 
or  mineralogical  character  of  the  ground  upon  which  it 
crawls  or  alights.  A  few  rare  inorganic  bodies  do  indeed 
possess  the  requisite  simplicity  and  richness  for  the  sup- 
posed first  stimulus,  as  we  see  in  the  ruby,  the  emerald, 
the  sapphire,  and  the  topaz ;  nay,  some  much  commoner 
substances,  such  as  red  sandstone  and  blue  granite,  are 
endowed  with  a  moderately  bright  and  pure  colour.  All 
these  bodies,  however,  lie  open  to  the  fatal  objection  that 
they  do  not  in  any  way  contribute  to  the  welfare  of  the 
insect  or  animal  which  looks  upon  them.  A  sense  highly 
developed  by  other  means  may  (as  we  see  in  the  savage 
or  barbarous  love  for  precious  stones)  be  agreeably  exercised 
upon  such  objects  ;  but  in  order  to  give  that  sense  its  first 
start,  some  direct  advantage  must  be  secured  by  the  new 
mode  of  discrimination,  either  in  the  pursuit  of  food,  the 
search  for  mates,  or  the  avoidance  of  enemies.  No  faculty 
can  possibly  be  originally  developed  for  the  sake  of  mere 
useless  exercise  upon  unessential  acts ;  altliough,  as  we 
shall  see  when  we  come  to  examine  the  aesthetic  value  of 
colour,  each  faculty,  when  once  fully  established,  admits 
of  immense  pleasurable  extension  by  being  directed  to- 
wards such  secondary  ends. 

The  same  line  of  argument  applies  to  those  occasional 
displays  of  colour  which  are  due  to  transient  effects  of 


INSECTS  AND  FLOWERS.  35 

sunlight,  tlirough  the  medium  of  a  refractive  vapour. 
Long  before  the  first  insect  vision  learnt  to  discriminate 
between  red,  yellow,  and  blue,  the  various  rays  which  we 
call  by  those  names  poured  down  unnoticed  upon  the 
primeval  world.  Then,  as  now,  the  rainbow  scattered 
ten  thousand  colours  upon  the  dull  grey  clouds,  but  no 
eye  drank  in  the  diverse  stimulation  from  its  gorgeous 
undertones  of  melting  orange  and  exquisite  green.  Then, 
as  now,  the  sunset  crimsoned  the  west  with  dying  glory, 
and  bathed  the  horizon  in  floods  of  golden  light,  but 
no  living  thing  beheld  its  loveliness  or  revelled  in  its 
changeful  wealth.  Such  distant  and  exceptional  displays 
could  have  little  or  no  effect  upon  the  life  of  tiny  creatures 
that  picked  out  in  fear  and  trembling  a  precarious  liveli- 
hood amid  palaeozoic  forest  shades.  Even  our  own  nearest 
mammalian  relatives  seem  totally  unconcerned  with  regard 
to  the  magnificent  pictures  which  are  spread  nightly 
before  their  eyes  in  tropical  plains.  Indeed,  the  savage 
members  of  our  own  race,  or  even  the  stolid  peasantry 
of  European  countries,  appear  to  notice  such  useless 
phenomena  with  little  curiosity  or  admiration.  Part  of 
our  business  in  this  work  will  be  to  trace  out  the  slow 
steps  by  which  the  love  of  bright-coloured  food  led  on  to 
the  choice  of  bright- coloured  mates ;  and  how  this  again 
brought  about  a  liking  for  bright  colours  in  general,  which 
shows  itself  in  the  savage  predilection  for  brilliant  dyes 
and  glistening  pebljles ;  till  at  last  the  whole  long  series 
culminates  in  that  intense  and  unselfish  enjoyment  of  rich 
and  pure  tints  which  makes  civilised  man  linger  so  lovingly 
over  the  hues  of  sunset  and  the  myriad  shades  of  autumn. 
But  if  even  the  lower  types  of  humanity  are  little  stirred 
by  such  glowing  sights,  how  could  we  expect  the  humble 
insect  to  have  developed  a  new  sense  for  their  perception? 
Here,  as  elsewhere,  the  disinterested  affection  can  only  be 
reached  by  many  previous  steps  of  utilitarian  progress. 

It  is  to  the  organic  world,  then,  the  insect's  practical 
world  of  food  and  prey,  that  we  must  look  for  the  first 


36  THE  COLOUR-SENSE. 

development  of  the  colour-sense.  In  the  origin  of  flowers 
we  shall  find  also  the  origin  of  the  insect's  perception ; 
and  though  the  inquiry  will  seem  at  first  to  lead  us  rather 
far  afield  from  our  proper  path,  I  think  we  cannot  do  better 
than  steadily  set  to  work  at  unravelling  the  tangled  thread 
of  their  mutual  influence.  In  order  to  do  so  effectively 
we  must  first  glance  at  the  condition  of  the  world  before 
flowers,  fruit,  or  colour-sense  had  yet  begun  the  first  stages 
of  their  reciprocal  existence. 

Brongniart  long  ago  pointed  out  that  the  periods  of 
jieolofrical  vecretation  fall  into  three  main  divisions,  which 
he  called  the  reigns  of  acrogens,  of  gymnosperms,  and  of 
angiosperms.  Acrogens  are  plants  like  ferns  and  mosses, 
which  bear  no  fruits  or  fiowers,  but  produce  their  young 
by  means  of  spores,  Gymnosperms  are  plants  like  pines 
and  firs,  which  have  their  blossoms  and  seeds  in  dry  scaly 
cones.  Angiosperms  are  true  flowering  plants,  often  bear- 
ing bright  bells  or  brilliant  clusters  of  bloom,  and  always 
having  their  seeds  enclosed  in  some  more  or  less  con- 
spicuous form  of  enveloping  fruit.  These  three  kinds  of 
plants  succeeded  each  other  through  the  geological  series 
in  the  order  here  assigned  to  them — members  of  every 
class  still  surviving  on  our  earth,  but  outnumbered  and 
overlived,  as  a  rule,  by  those  of  the  newer  and  more  suc- 
cessful classes. 

For  our  present  purpose,  however,  we  might  say  more 
truly  that  the  great  epochs  of  vegetal  life  naturally  fall  under 
three  similar  heads — the  reign  of  flowerless  plants,  the  reign 
of  wind-fertilised  flowering  plants,  and  the  reign  of  insect- 
fertilised  flowering  plants.^  These  three  heads  correspond 
in  the  main  with  Brongniart's  divisions,  but  they  serve  to 
bring  more  clearly  into  prominence  the  salient  f  anctional 
facts  with  which  we  are  here  especially  concerned. 

Flowerless  plants,  or  cryptogams,  are  those  which  have 

1  See  an  excellent  article  on  "  The    in  the  "Popular  Science  Review  "  for 
Geological  Antiquity  of   Insects  and    January  1878. 
flowers,"  by  Mr.  J.  E.  Taylor,  F.G.S,, 


INSECTS  AND  FLOWERS.  37 

no  conspicuous  organs  for  the  production  of  seeds  or  fruits. 
Their  chief  varieties  are  known  to  all  as  fungi,  sea- weeds, 
mosses,  and  ferns.  Floweriug  plants,  or  phanerogams,  are 
those  which  possess  more  or  less  conspicuous  organs  for 
the  production  of  seeds  and  fruits.  They  may  he  divided, 
not  structurally  but  functionally,  into  two  great  sub- 
classes— the  anemophilons  and  the  entomophilons.  Ane- 
mophilous  plants  include  all  species  in  which  the  pollen 
of  the  male  flower  is  wafted  to  the  stigma  of  the  female 
flower  by  means  of  the  wind.  Entomophilous  plants 
include  all  species  in  which  the  pollen  is  carried  to  the 
stigma  upon  the  head,  legs,  or  bodies  of  insects.  Each  of 
these  classes  possesses  numerous  species  in  which  various 
modifications  have  been  produced  to  aid  fertilisation  by 
the  appropriate  means.  Some  of  these  modifications  we 
shall  examine  as  we  proceed ;  for  others,  the  inquirer  must 
be  referred  to  special  works  upon  the  subject.^ 

In  the  great  forests  of  the  Carboniferous  era  few  or  no 
flowers  diversified  the  unbroken  green  of  the  primeval 
w^orld.  Almost  all  the  plants  which  raised  their  heads 
above  the  dark  mould  of  those  forgotten  deltas  were  acro- 
gens  or  other  cryptogams.  Like  the  ferns  and  mosses  of 
our  own  epoch,  they  reproduced  their  kind,  not  by  means 
of  flowers  and  seeds,  but  by  inconspicuous  little  spores,  each 
of  which  rooted  itself  on  the  ground  independently,  and 
grew  into  a  young  plant.  Many  of  them  resembled  the 
bristling  horse-tails  of  modern  waste  lands,  magnified  a 
hundred-fold,  so  as  to  present  the  appearance  of  huge 
jointed  trees,  to  which  geologists  have  given  the  name  of 
calamites.  Others  were  rather  the  gigantic  analogues  of 
our  creeping  club-mosses,  with  monstrous  tliickened  stalks, 
clad  in  a  sort  of  plated  armour,  and  known  to  science  as 
sigillarice,  lepidodendra,  and  halonice.  Yet  others,  again, 
grew  like  the   tree-ferns  of   our  latter-day  tropics,  with 

1  See,  in  particular,  Mr.  Darwin  on  Flowers  in  their  Relation  to  Insects," 
the  "Fertilisation  of  Orchids,"  Sir  and  the  works  of  Sprengel,  Delpino, 
John    Lubbock    on    "British    Wild    and  H.  Miiller. 


38  THE  COLOUR-SENSE. 

graceful  waving  fronds,  whose  delicate  outline  is  still 
faithfully  preserved  on  the  flat  surface  of  many  a  coal- 
seam.  But  amongst  them  all  not  a  single  bright  blossom 
anywhere  displayed  its  crimson  petals  or  its  golden  bells ; 
not  a  single  fruit  gleamed  red  or  orange  among  the  em- 
bowering foliage.  Green,  and  green,  and  green  once  more ; 
wherever  the  eye  of  an  imaginary  visitor  could  turn,  it 
would  have  rested  on  one  unbroken  sea  of  glistening 
verdure. 

A  few  phanerogams  there  were,  it  is  true,  among  this 
mass  of  cryptogamic  vegetation,  but  they  belonged  entirely 
to  the  pine  and  cycad  families,  which  grow  their  seed 
in  hard  scaly  cones,  and  would  never  be  included  amongst 
the  flowering  plants  by  any  but  a  technical  botanist. 
Moreover,  as  their  blossoms  are  green  when  young  and 
brown  when  ripe,  they  would  form  little  or  no  exception 
to  the  prevailing  tints  of  the  palaeozoic  world.  Even  if  a 
few  primitive  grasses  of  some  archaic  form  intermingled, 
as  is  possible,  with  the  mosses  and  liverworts  which  car- 
peted the  ground  beneath  the  conifers,  the  tree-ferns,  and 
the  titanic  lycopodites,  yet  these  themselves  would  bear 
their  seed  in  green  panicles  on  a  waving  stem,  and  would 
still  add  no  new  element  of  colour  to  the  one  monotonous 
field.  ISTot  a  trace  of  any  vegetal  organism  has  yet  been 
discovered  in  the  primary  rocks  to  which  we  can  even 
conjecturally  attribute  a  possible  tinge  of  red  or  orange, 
blue  or  yellow,  in  the  form  of  flowers  or  fruit. 

Equally  unvaried,  no  doubt,  was  the  hue  of  the  articu- 
late creatures  which  fed  amid  those  green  jungles  of  tangled 
fern  and  club-moss.  A  few  scorpion-like  insects,  an  occa- 
sional cockroach,  beetle,  or  other  uncanny  creeping  thing, 
may  still  be  detected  in  the  dehris  of  a  forgotten  world ; 
but  no  trace  of  a  bee,  a  moth,  or  a  joyous  butterfly  can  be 
discovered  in  these  earliest  ai^es  of  animal  life.     Scarlet 

o 

berry  and  crimson  blossom,  gorgeous  bird  and  painted  in- 
sect, were  all  equally  absent  from  the  unvaried  panorama 
of  careen  overhead  and  brown  beneath. 


INSECTS  AND  FLOWERS.  39 

Such,  we  may  suppose,  was  the  general  appearance  of  our 
earth's  surface  before  the  colour-sense  had  given  rise  to  all 
the  diverse  wealth  of  hues  which  gladden  the  woodland 
and  the  meadow  for  modern  eyes.  First  to  be  developed 
among  the  bright-coloured  objects  of  the  newer  era  were 
the  brilliant  whorls  of  abortive  leaves  which  ordinary 
people  know  as  flowers.  Their  origin  affords  us  the  key 
to  all  the  subsequent  evolution  both  of  coloured  organisms 
and  of  the  sense  whereby  they  are  perceived. 

Tlie  transition  from  the  wholly  green  and  spore-bearing 
cryptogams  to  the  bright  hues  of  entomophilous  blossoms 
was  through  the  intermediate  stage  of  anemophilous 
plants.  Already,  in  the  Carboniferous  era  of  the  palaeozoic 
world,  we  have  seen  that  these  org^anisms  had  bef]jun  to 
exist.  The  causes  which  led  to  their  development  throw 
so  much  light  upon  the  subsequent  evolution  of  insect- 
fertilised  species,  that  we  must  pause  for  a  moment  to 
examine  the  history  of  their  first  appearance. 

Every  individual  cryptogamic  plant'  produces  spores  or 
young  individuals  by  its  own  unaided  generative  power. 
It  needs  no  co-operation  from  a  partner  of  a  different  sex 
to  fertilise  the  embryo  germs  which  it  puts  forth.  True, 
a  male  and  a  female  element  may  always  be  discovered 
within  the  plant  itself ;  but  their  occurrence  does  not  mili- 
tate against  the  general  statement  that  cryptogamic  repro- 
duction is  essentially  hermaphrodite  or  non-sexual  in  its 
character,  For  real  sexual  generation  consists  funda- 
mentally in  this,  that  two  independent  parents  combine 
to  produce  a  brood  of  young,  partaking  equally,  on  the 
average,  of  the  idiosyncrasies  of  each.  Now,  Mr.  Darwin 
has  shown  1  that  whenever  an  organism  is  the  result  of 
interaction  between  two  anterior  organisms,  it  possesses 
a  vigour,  a  plasticity,  and  a  hardiness  wdiich  enable  it  to 
thrive  far  more  easily  than  any  similar  organism  resulting 
from  the  generative  action  of  a  single  parent.  Our  great 
teacher   has  proved   that  self-fertilised   flowers  produce 

^  On  "  Cross-Fertilisation," /jassm. 


40  THE  COLOUR-SENSE, 

relatively  weak,  puny,  and  unhealthy  young ;  while  cross- 
fertilised  flowers  produce  relatively  strong,  hearty,  and 
vigorous  young.  The  general  principle  upon  which  this 
effect  depends  has  been  exposed,  with  his  usual  luminous 
insight,  by  Mr.  Herbert  Spencer;^  but  unfortunately  its 
explanation  would  involve  too  many  wide  questions  of 
biological  theory  for  reproduction  here. 

If,  then,  by  any  special  combination  of  circumstances, 
it  should  happen  at  any  time  that  certain  plants  acquired 
the  habit  of  fertilising  the  female  element  in  one  individual 
by  the  male  element  of  another,  it  would  necessarily  re- 
sult that  such  plants  would  produce  exceptionally  healthy 
yaung,  and  so  gain  unusual  advantages  for  their  descen- 
dants in  the  struggle  for  life.  And  this  is  exactly  the 
case  with  flowering  as  opposed  to  flowerless  plants.  While 
the  latter  still  continue  to  fertilise  themselves  in  every 
instance,  the  former  possess  a  special  set  of  male  and 
female  organs,  often  situated  on  different  individuals,  and 
almost  always  so  di&posed  that  the  pollen  of  any  particular 
flower  is  specially  prevented  from  quickening  the  ovules 
of  its  own  pistil.  Indeed,  the  very  effect  which  Mr. 
Darwin's  experiments  show  us  on  a  small  scale,  nature 
herself  here  shows  us  on  a  large  scale  \  for  when  once  the 
flowering  plants  had  been  introduced  into  the  world,  their 
superior  vitality  gave  them  such  an  increased  chance  in 
the  struggle  for  life  that  they  have  now  overrun  the  whole 
earth,  and  almost  lived  down  the  very  memory  of  their 
cryptogamic  predecessors,  whose  huge  forms  diversified  the 
landscape  of  a  paleozoic  wild.  Step  by  step,  throughout 
the  secondary  and  tertiary  periods,  we  find  the  acrogens 
decreasing  in  number  of  species,  in  frequency  of  indivi- 
duals, in  size  and  height ;  while  step  by  step  we  find  the 
flowering  plants  dispossessing  them  over  the  whole  world, 
and  growing  into  more  and  more  varied  forms,  with  ever- 
increasing  numbers  and  ever-widening  girth ;  until  at  last 
forest  trees,  and  herbs,  and  grasses  cover  the  face  of  hill, 

1  Principles  of  Biology,  vol.  i.  chap.  x. 


INSECTS  AND  FLOWERS.  41 

and  plain,  and  valley ;  while  only  in  a  few  tropical  jungles, 
or  a  stray  patch  of  neglected  English  warren,  do  we  still 
discover  the  degenerate  descendants  of  those  giant  tree- 
ferns  and  horse-tails  which  flourished  without  a  rival  over 
vast  continents  during  the  earlier  ages  of  vegetal  life. 

Among  these  flowering  plants,  which  thus  substituted 
the  sexual  for  the  hermaphrodite  method  of  reproduction, 
the  anemophilous  or  wind-fertilised  division  was  the  first 
to  appear.  The  ever-moving  currents  of  air  naturally 
offer  the  earliest  and  simplest  agency  for  the  dispersion 
and  transference  of  pollen  from  the  stamens  of  one  blos- 
som to  the  pistil  of  another.  Accordingly,  we  find  the 
pines  and  cycads,  both  of  which  bear  their  flowers  in  the 
form  of  cones  or  other  unnoticeable  bunches  of  floral 
organs,  as  the  earliest  representatives  of  flowering  plants. 
After  them,  in  geological  order,  come  the  monocotyledons, 
represented  by  grasses,  rushes,  and  other  spiky  species, 
whose  blossoms  assume  the  shape  of  green  panicles  or 
waving  plumes ;  while,  last  of  all,  come  the  dicotyledons, 
whose  anemophilous  varieties  are  usually  distinguished  by 
those  pretty  hanging  clusters  of  stamens  or  pistils  which 
we  know  as  catkins.  Now,  in  all  these  cases,  the  mature 
male  organs,  covered  with  the  fertilising  pollen,  necessarily 
protrude  from  the  scales,  sheathes,  or  glumes  which  guard 
their  younger  stage,  and  offer  large  surfaces  to  the  wind, 
whose  aid  they  require  in  the  dispersion  of  their  stores. 
Similarly,  the  pistils  or  female  organs  must  possess  spread- 
ing and  feathery  stigmatic  processes,  wherewith  to  catch 
any  stray  grains  of  pollen  which  the  unconscious  wind 
may  waft  to  their  neighbourhood.  Hence  these  blossoms 
consist  usually  of  bundles  or  masses  of  male  and  female 
organs,  hanging  out  in*  such  a  way  as  to  secure  the  favour 
of  every  passing  breeze;  but  they  never  possess  those 
bright  whorls  of  coloured  leaves  which  make  up  the  popular 
idea  of  a  flower.  The  latter  notion  is  mainly  based  upon 
the  peculiar  structure  of  entomophilous  plants. 

As  wind- fertilised  flowers  can  only  hope  that  a  small 


42  THE  COLOUR-SENSE. 

fraction  of  their  pollen  will  reach  the  stigmatic  surface 
of  their  brides,  and  there  be  drunk  in  to  fertilise  the  em- 
bryo within,  they  must  needs  produce  enormous  quan- 
tities of  useless  material,  to  be  dissipated  by  the  storm  in 
every  direction.  The  amount  of  pollen  thus  wasted  is 
often  incredibly  great.  The  floor  of  a  pine  forest  during 
the  flowering  season  frequently  lies  thickly  covered  with 
the  rich  yellow  dust  that  cost  so  much  useless  energy  to 
the  parent  plant.  Occasionally  even  showers  of  pollen 
grains  have  been  noted  in  the  neighbourhood  of  great 
forests  or  of  fields  thickly  sown  with  anemophilous  spe- 
cies. At  Mumbles,  near  Swansea,  a  yellow-coloured  rain 
fell  in  1850,  and  left  large  spots  of  ochre-like  matter, 
which  proved  on  close  examination  to  consist  of  willow- 
pollen.^  Similar  showers,  produced  by  the  Canadian 
conifers,  have  often  been  observed  along  the  shore  of  the 
great  lakes,  and  others  have  taken  place  in  Zurich,  in 
Brunswick,  and  in  Inverness-shire.  Of  course,  the  loss 
of  energy  which  this  waste  expenditure  involves  for  the 
parent  plant  must  necessarily  be  very  great ;  and  any 
change  in  its  circumstances  which  produced  a  more  econo- 
mical mode  of  applying  the  pollen  to  the  pistil  would 
naturally  result  in  a  saving  of  material,  and  so  give 
the  plants  in  which  it  occurred  a  fresh  advantage  over 
their  less  fortunate  compeers.  Such  a  change  we  see 
in  the  utilisation  of  insect  agency  by  the  entomophilous 
plants. 

Even  as  early  as  the  Carboniferous  period  we  find  traces 
of  terrestrial  articulates  which  might  have  sought  their 
food  among  the  few  coniferous  blossoms  of  that  mainly 
flowerless  world.  Most  of  the  plants  about  them  were 
hard,  scaly,  innutritions  acrogens,  whose  stem  and  leaves 
contained  large  quantities  of  silica,  as  we  still  see  to  be 
the  case  in  the  horse-tail  family,  their  nearest  modern 
allies.  But  the  stray  flowering  species  which  grew  at 
rare  intervals  in  the  midst  of  the  calamites  and  lepido- 

^  Balfour's  Class-Book  of  Botany,  p.  562. 


INSECTS  AND  FLOWERS.  43 

dendra  must  have  offered  special]  attractions  to  insects 
(or  their  undifferentiated  ancestors)  in  the  shape  of  soft, 
edible,  nutritious  pollen.  And  as  the  insects  travelled 
from  one  flower  to  another,  carrying  on  their  legs  or  heads 
the  fertilising  powder,  they  would  supply  the  plant  with 
a  cheaper  and  more  certain  means  of  impregnation  than 
that  afforded  by  the  wasteful  wind.  Accordingly,  any 
plants  which  offered  special  advantages  to  insects,  in  the 
shape  of  pollen,  sweet  juices,  or  soft  edible  matter,  would 
thus  obtain  an  extra  chance  in  the  general  competition 
for  a  share  of  the  earth's  surface,  and  hand  down  the 
peculiarity  to  an  ever-increasing  brood  of  descendants. 
So,  when  once  the  entomophilous  flora  began  to  exist,  it 
gained  ground  rapidly  on  the  anemophilous  division,  as 
the  anemophilous  flora  had  previously  gained  ground  on 
the  fiowerless  plants,  until  in  our  own  day  the  two  divi- 
sions divide  the  world  between  them ;  while  in  the  future, 
doubtless,  the  balance  will  be  still  further  disturbed  in 
favour  of  the  younger  and  more  vigorous  races.^ 

Of  course,  the  change  from  fertilisation  by  wind  to 
fertilisation  by  insects  could  not  be  accomplished  without 
many  structural  modifications,  whereby  the  flower  became 
adapted  to  the  new  and  more  specialised  agency  thus 
afforded  it.  Some  of  these  modifications  were  concerned 
with  the  food  offered  by  the  flower  to  the  fertilising 
insect.  At  first  this  food  doubtless  consisted  of  pollen 
alone,  but  after  a  time  there  was  added  that  sweet  matter 
known  as  sugar  or  honey,  wdiich  is  contained  more  or  less 
in  most  plants,  and  which  is  especially  developed  during 
the  two  processes  of  flowering  and  fruiting.  Now  sugar, 
by  its  crystalline  condition,  so  rare  amongst  energy-yield- 

1  The  botanical  critic  need  hardly  adaptive  accident.  The  general  reader 

be  told  that  I  am  here  intentionally  would  only  be  confused  by  constant 

neglecting    the     more    deep-seated  references    to  the   cross-division    of 

structural  differences,  which  depend  monocotyledons    and     dicotyledons, 

upon  the  line  of  descent,   and  con-  especially  when  complicated  by  the 

sidering    only   the    superficial   func-  peculiar    geological    position   of   the 

fi07ia^  differences,  which  depend  upon  gymnosperms. 


44  THE  COLOUR-SENSE. 

ing  organic  products,  seems  specially  adapted  for  afford- 
ing pleasurable  stimulation  to  the  gustatory  nerves  of 
animals ;  ^  and  it  has  therefore  been  stored  up  by  plants 
in  all  those  cases  where  the  attraction  of  some  animal 
ally  is  desirable  for  their  protection  or  the  continuance  of 
their  species.  Certain  plants  lay  it  by  in  glands  upon 
their  stems  to  allure  the  harmless  ants  who  protect  them 
from  the  ravages  of  their  leaf-cutting  congeners.^  Others, 
again,  as  we  shall  see  in  a  later  chapter,  collect  it  in  the 
pulpy  covering  of  their  seed-vessels,  and  thus  induce 
parrots,  pigeons,  or  monkeys  to  devour  and  distribute  the 
undigested  kernel.  Yet  others  distil  it  in  the  recesses  of 
their  blossoms,  and  so  tempt  the  bee,  the  butterfly,  or  the 
humming-bird  to  rifle  their  labyrinthine  storehouses,  and 
unconsciously  aid  in  the  impregnation  of  their  embryos. 
The  honey  thus  elaborated  by  the  flower  has  become  at 
last  the  main  ultimate  attraction  for  all  fertilising  insects, 
whose  most  specialised  forms  we  find  in  the  common  hive- 
bees  of  domestic  economy. 

A  second  class  of  modifications  is  connected  with  the 
shape  of  the  flower.  Most  entomophilous  blossoms  pos- 
sess, in  addition  to  the  pistil  and  the  stamens,  two  other 
whorls  of  floral  leaves — the  corolla  and  the  calyx.  In  the 
simplest  form  of  flower,  these  whorls  consist  of  separate 
leaves  (petals  and  sepals),  as  we  see  in  the  buttercup  or  the 
dog-rose.  But  in  certain  more  specialised  flowers  the  long- 
continued  action  of  the  insect-fertilisers  has  unconsciously 
selected  those  blossoms  which  most  easily  suited  them- 
selves to  the  form  of  their  visitor,  and  has  thus  produced 
a  united  corolla,  all  whose  petals  are  joined  into  a  regular 
tube  or  cup,  as  we  see  in  the  Canterbury  bell,  the  con- 
volvulus, and  the  lily  of  the  valley.  A  number  of  these 
tubular  flowers  united  form  the  head  of  the  daisy,  the 
marigold,  and  the  sunflower.  In  still  more  specialised 
cases  the  cup  becomes  irregularly  lobed,  so  as  to  suit  still 

1  See  my    "Physiological    JSstlie-  ^  F.  Miiller  in  "  Nature,"  June  7, 

tics,"  p.  68.  1877. 


INSECTS  AND  FLOWERS.  45 

more  closely  the  shape  of  its  insect  friend — a  change 
whose  first  steps  we  see  in  honeysuckle  and  foxglove, 
while  its  completed  stage  is  shown  in  mint,  dead-nettle, 
snapdragon,  lobelia,  and  orchids.  All  these  varieties  of 
entomophilons  flowers  we  shall  have  to  examine  at  greater 
length  hereafter. 

But  the  third  class  of  modifications,  the  important  class 
for  our  present  subject,  is  that  which  refers  to  the  colouring 
of  flowers.  By  far  the  most  conspicuous  difference  between 
entomophilous  and  anemophilous  blossoms  is  the  difference 
of  colour.  While  wind-fertilised  plants  have  seldom  more 
than  a  few  brownish  scales  or  tiny  green  sepals  around 
their  fructifying  organs,  insect-fertilised  plants  are  almost 
always  distinguished  by  the  growth  of  large,  brilliantly- 
coloured  petals  outside  the  essential  whorls,  which  act  as 
guides  and  allurements  to  the  eyes  of  bees  or  butter- 
flies. These  wide,  expanded,  and  costly  structures  have 
absolutely  no  other  purpose  in  the  vegetal  economy  than 
that  of  attracting  the  fertilising  agents ;  and  they  afford 
by  themselves  a  strong  presumption  of  developed  colour- 
sense  in  the  creatures  for  whose  guidance  they  have  been 
slowly  evolved.  Let  us  see  by  what  steps  they  can  gradu- 
ally have  reached  their  present  conspicuous  dimensions. 

We  will  suppose  that  some  of  the  flowering  plants  in 
the  early  ages  of  the  world  showed  some  slight  tendency 
to  develop  the  various  attractive  structures  which  we 
now  observe  in  their  completed  form.  They  offered  to 
insects  the  soft  and  nourishing  pollen,  and  perhaps,  too, 
small  quantities  of  stimulating  saccharine  matter.  Such 
saccharine  matter  we  know  is  always  evolved  during  the 
opening  of  flowers,  at  least  in  small  amounts,  for  the 
nurture  of  the  blossom  itself;  and  there  is  nothing  extra- 
vagant in  the  supposition  that  occasional  individuals  might 
produce  it  in  more  than  the  average  quantity,  and  so  might 
attract  more  than  the  average  share  of  insect  attention. 
In  like  manner  they  may  possibly  have  shown  a  tendency 
to  develop  bright-coloured  leaves  around  their  essential 


46  THE  COLOUR-SENSE. 

organs ;  and  if  the  eyes  of  insects  were  capable  of  distin- 
guishing these  bright  colours,  in  however  imperfect  a 
degree,  it  would  naturally  follow  that  the  hues  would  go 
on  deepening  from  generation  to  generation  among  the 
plants,  while  the  perception  would  go  on  sharpening  itself 
from  generation  to  generation  among  the  insects.  For 
while  the  flowers  which  thus  become  more  and  more 
readily  distinguishable  by  their  fertilisers  would  thereby 
better  secure  the  chance  of  descendants,  the  insects  which 
most  readily  distinguished  flowers  would  thereby  secure 
for  themselves  the  greatest  amount  of  the  available  food- 
stores.  So  that,  supposing  such  a  tendency  once  set  up 
on  either  side,  we  can  see  every  reason  why  it  should 
ultimately  develop  to  its  present  noticeable  extent. 

This,  however,  is  mere  a  'priori  hypothesis.  The  experi- 
mental philosopher  will  ask  at  once  whether  we  have  any 
grounds  for  believing  that  the  tendency  in  point  would 
ever  be  set  up.  I  think  we  have  such  grounds  in  abun- 
dance, and  although  the  question  involves  a  little  closer 
application  and  more  technical  considerations  than  any  we 
have  yet  encountered,  I  shall  ask  the  reader  patiently  to 
follow  me  through  the  exposition,  because  it  really  encloses 
the  whole  fundamental  basis  of  the  developed  colour-sense 
in  every  terrestrial  animal.  The  point  which  we  have  first 
to  consider  is  this  :  Did  flowers  show  an  original  tendency 
to  the  production  of  coloured  adjuncts  prior  to  the  selec- 
tive action  of  insects  ?  And  when  we  have  answered  that 
question  we  must  proceed  to  the  second  one  :  Did  insects 
possess  any  tendency  vaguely  to  discriminate  colours 
apart  from  the  reactive  influence  of  entomophilous 
flowers  ? 

The  solar  radiations,  falling  upon  the  green  portions 
of  plants,  are  the  sole  ultimate  source  of  all  the  energy 
existing  in  the  animal  or  vegetal  organism.  Under  their 
influence,  the  plant  separates  carbon  and  hydrogen  from 
the  oxygen  with  which  they  were  originally  combined, 
stores  them  up  in  some  part  of  its  own  tissues,  and  turns 


Los  Angeles,  Cal. 

INSECTS  AND  FLOWERS.  47 

the  free  oxygen  adrift  iipoii  the  atmosphere  around.  In 
this  process,  the  kinetic  or  active  energy  of  the  solar 
undulations  has  assumed  the  potential  or  dormant  form. 
The  potential  energy  thus  laid  up  is  associated  with  the 
carbon  and  hydrogen  of  the  plant  on  the  one  hand,  and 
with  the  free  oxygen  of  the  atmosphere  on  the  other. 
Whenever  they  may  recombine,  the  dormant  energy  will 
assume  once  more  the  active  form,  and  be  yielded  up  in 
the  shape  of  mechanical  motion,  heat,  or  light. 

This  reconversion  of  contained  energy  into  its  mobile 
mode  may  be  brought  about  in  many  ways.  Sometimes 
the  plant  may  be  cut  down  and  burnt,  as  we  all  see  in 
wood-fires,  and  then  the  energy  will  be  given  out  rapidly 
as  heat  and  light,  while  part  of  it  will  also  go  off  as  motion 
of  the  surrounding  air.  Sometimes  the  plant  may  fall  as 
it  lies,  be  changed  into  peat  or  coal,  and  finally  burnt,  like 
the  w^ood,  in  a  human  grate,  with  the  same  concomitant 
phenomena  as  in  the  first  case.  Sometimes,  too,  these 
same  materials — w^ood,  coal,  peat — may  be  used  to  feed  a 
steam-engine,  and  mainly  converted  into  visible  move- 
ments of  the  locomotive  or  its  parts,  which  are  finally 
dissipated  by  friction  into  the  circumambient  aether.  In 
yet  other  cases,  the  plant  may  be  eaten  by  an  animal,  and 
then  its  elements  will  recombine  within  his  body  with 
the  free  oxygen  supplied  by  his  lungs  or  gills,  and  will 
give  off  heat  and  motion,  less  conspicuously  perhaps,  but 
quite  as  truly  as  in  the  engine.  There  remains,  however, 
another  instance,  fully  as  common  as  these,  yet  far  less 
generally  observed — the  instance  in  which  the  elements 
recombine  in  the  tissues  of  the  living  plant,  and  yield  up 
their  dormant  energies  in  producing  growth,  development, 
and  rearrangement  of  its  parts.  This  metamorphosis  of 
energy  (known  as  Stoffcuechsel  or  Metastasis)  actually  takes 
place  in  every  active  portion  of  a  plant  which  does  not 
itself  assimilate  nutritive  material  from  the  surrounding 
air.  And  all  such  parts  of  plants  may  be  considered  as 
carrying  on  essentially  animal  functions — that  is  to  say, 


48  THE  COLOUR-SENSE. 

functions  by  which  potential  energy  becomes  kinetic, 
oxygen  unites  with  carbon  to  form  carbonic  anhydride, 
heat  is  evolved,  and  motion  is  given  out. 

The  most  noticeable  eases  of  such  quasi-animal  processes 
may  be  seen  in  the  germination  of  s^eds,  the  growth  of 
bulbs  and  tubers,  the  unfolding  of  flowers,  and  the  ripening 
of  fruits.  In  fact,  every  growing  and  active  part  of  a 
plant,  unless  it  be  itself  assimilating  kinetic  energy  from 
solar  undulations,  must  necessarily  be  using  up  energies 
assimilated  elsewhere.  Otherwise,  it  would  be  manufac- 
turing new  energies  for  itself  out  of  nothing,  which  we 
know  to  be  impossible,  and  inconceivable  as  a  direct  con- 
travention of  all  physical  and  mental  laws. 

Now,  the  active  agent  of  deoxidation  in  ordinary  plants 
is  that  peculiar  compound  substance  known  as  chlorophyll, 
the  pigment  which  gives  a  green  ■colour  to  healthy  leaves. 
Hence  all  the  active  organs  of  plants  are  usually  green  in 
hue,  because  the  chlorophyll  is  seen  through  the  transparent 
cell-walls  of  the  epidermis.  But  there  are  reasons  for 
believing  that  wherever  the  reverse  process  of  metastasis 
is  taking  place,  other  bodies  are  frequently  formed,  which 
reflect  the  light  in  slightly  different  manners,  and  so  give 
rise  to  tints  of  red,  orange,  yellow,  pink,  mauve,  purple,  or 
blue.  We  will  examine  the  evidence  in  order,  and  see 
whether  we  can  gather  from  it  any  inference  as  to  the 
origin  of  coloured  flowers.^ 

In  the  first  place,  even  in  active  leaves,  the  presence  of 
green  chlorophyll  is  often  masked  by  the  occurrence  of 
other  pigments,  which  give  the  foliage  a  tinge  of  brown, 
russet,  scarlet,  or  golden  yellow.     Cases  of  this  sort  are 

1  In  the  succeeding  argument  I  have  636),  "becaTise   the    results    hitherto 

neglected  for  a  while  the  difficult  eh  em-  reached  are  still  somewhat  indefinite, 

ical  question  of  the  relations  between  and  becaiise  the  consideration  of  the 

chlorophyll, xanthophyll,erythrophyll,  chemical  changes  involved  is  better 

and  the  other  colouring  matters  of  relegated  to  the  end  of  the  physical 

plants    (see    Sorby   in    Proc.    Royal  and  physiological  inquiry,  upon  wliich 

Soc,  vol.  XV.  p.  433,  and  vol.  xxi.  we  must  now  enter.     A  fuller  state- 

p.  442 ;  also  in  the  English  version  ment  on  this  point  will  be  found  on 

of  Sach's  Teit-Book   of  Botany,  p.  a  later  page. 


INSECTS  AND  FLOWERS.  49 

commonly  known  in  the  copper  beech,  the  red  cabbage, 
and  the  various  species  of  purple  coleus,  crimson-hearted 
caladium,  pink  dracsena,  or  pale  mauve  begonia.  Here 
the  colouring  matter  doubtless  belongs  to  some  one  among 
the  many  by-products  of  vegetal  physiology,  which  must 
necessarily  occur  from  time  to  time  in  one  part  or  another 
as  the  results  of  assimilative  or  metastatic  changes.  But 
in  the  more  noticeable  cases  of  coloured  juices  or  pig- 
ments, other  than  green,  we  shall  find  that  the  special 
colouring  matter  is  almost  always  more  or  less  connected 
with  those  portions  of  the  plant  where  energy  is  being 
liberated,  and  where  accordingly  oxidation  is  necessarily 
taking  place. ^ 

The  only  class  of  plants  in  which  green  rarely — we 
might  almost  say  never — occurs,  is  that  of  fungi.  But 
fungi  differ  from  all  other  plants  (except  a  few  parasites 
and  saprophytes)  and  agree  with  animals  in  this,  that 
they  derive  their  energies  not  directly  from  solar  undula- 
tions, but  from  organised  matter  already  contained  in  the 
soil  or  matrix  on  which  they  grow.  And  there  is  some- 
thing in  the  vivid  orange,  yellow,  lilac,  and  crimson  of 
their  hues,  as  well  as  in  the  pasty  whiteness  of  their 
common  tissues,  which  strikingly  recalls  the  possibly 
adventitious  colouring  of  the  lower  animal  forms,  such  as 
sea-anemones,  starfish,  and  medusee.  This  analogy,  as  we 
shall  note  hereafter,  is  not  without  a  deep  significance  for 
our  present  purpose.^ 

When,  however,  we  go  on  to  those  plants  which  have 
normally  green  leaves,  we  see  a  like  result.  In  the  first 
place,  dying  leaves,  as  we  all  know,  assume  the  most  bril- 

^  See  on  the  whole  process  of  metas-  &c.     A  botanical  work  "which  should 

tasis,  Sach's  "Text-Book  of  Botany,"  extend  to    the   plant   organism  the 

p.    626,  seq.      It  is  to  be  regretted  same  strictly  physical  treatment  as 

that   the   author   of    this   otherwise  Hermann's  "Physiology"  applies  to 

lucid    and   valuable    book    has    not  the  animal  organism  is  still  a  desider- 

brought    more      prominently      into  atum. 

notice  the  question  of  the  energies  ^  See  also  Sorby,   in  Proc.   Eoy. 

involved,   and    the    transformations  Soc,  vol.  xxi.  pp.  475-480. 
which  they  undergo,  by  oxidation, 


so  THE  COLOUR-SENSE. 

liant  tints  of  red,  yellow,  orange,  and  brown.  Even  in 
our  own  damp  and  uncertain  climate,  the  Virginia  creeper 
dows  with  the  richest  crimson,  while  the  forest  trees 
shade  off  into  delicate  tones  of  golden  gloss  and  occasional 
flashes  of  deep  scarlet  light.  But  in  American  wood- 
lands these  displays  assume  grander  dimensions  and  more 
glorious  beauties,  forming  perhaps  the  most  magnificent 
fields  of  gorgeous  colour  in  the  whole  organic  world. 
Now,  Macaire-Princep  has  shown,^  that  as  leaves  begin  to 
turn  yellow  they  give  up  the  function  of  deoxidation, 
while  a  reverse  process  at  once  sets  in.  Mr.  Sorby  traces 
the  gradual  loss  of  vitality  in  the  fading  leaf  from  bright 
i^reen  throuc^h  crreenish-brown,  red,  scarlet,  and  orange- 
brown  to  the  final  dull  and  dingy  hue  of  the  dry  leaf.^ 
That  this  change  results  from  some  degradation  of  energy, 
in  whatever  component  of  the  leaf  it  may  take  place,  is 
beyond  all  doubt.^ 

Any  injury  to  leaves  causes  similar  -effects,  whether  due 
to  disease,  external  impact,  or  the  attacks  of  insects.  Gall- 
nuts  and  rose-blights  have  generally  an  outer  coating  of 
small  reddish  excrescences,  while  feeble  plants  produce 
yellow-spotted  or  pink-speckled  leaves.  Here,  too,  oxida- 
tion, or  some  other  de-energising  action,  is  most  probably 
the  cause  of  the  change  observed. 

Leaves  which  have  given  up  their  natural  functions 
frequently  assume  bright  hues.  Thus  the  pitchers  of  the 
side-saddle  flower  {Sarracenia  rubra)  have  purple  tips.* 
Those  of  the  pitcher-plant  {Nepenthe)  are  "tinted  and 
mottled  with  red  and  purple."^  The  leaves  of  the  curious 
insectivorous  plants,  with  whose  habits  Mr.  Darwin  has 
made  us  so  familiar,  are  apt  to  be  speckled  with  similar 
hues,  especially  in  the  active  portions,  which  show,  by 

1  Mem.  de  la  Societe  Phys.  et  •*  See  the  figure  in  Sir  W.  Hookers 
d'Hist.  Xat.  de  Geneve,  iv.  43.  "  Flora  Exotica,''  pi.  13. 

-  Ubi  supra,  and  "Nature,"  Jaim-  ^  Wallace,  "Malay  Archipelago," 
ary  19,  1871.  -p.  81. 

2  Quarterly    Journal   of    Science, 
1871,  p.  64,  and  1873,  p.  451. 


INSECTS  AND  FLOWERS.  51 

tlieir  movements  and  secretions,  some  approach  to  animal 
functions.  The  common  English  sundew  {Drosera  rotun- 
difolia),  which  may  be  found  in  all  boggy  or  peaty  places, 
has  bright  red  glands  scattered  over  its  leaves.  The 
Venus  fly-trap  {Dioncea  muscipula)  is  "thickly  covered 
with  minute  glands  of  a  reddish  or  purplish  colour/'  while 
the  spikes  which  close  upon  the  insect  prey  have  small 
projections  described  as  ''  reddish-brown  or  orange."  Like 
organs  in  Drosophyllum  lusitanicum  are  bright  pink,  and 
in  Finguicula  lusitanica  purple.^  Our  own  common 
butterwort  and  saxifrage,  which  share  to  a  less  extent  the 
same  peculiarity,  have  also  slightly  reddish  or  yellowish 
foliage. 

Parasites  which  live  upon  the  energetic  matter  stored 
up  by  other  plants  fall  obviously  under  the  same  class. 
Their  whole  existence  consists  in  a  continuous  metastasis, 
that  is  to  say,  in  the  expenditure  and  liberation  of  pre- 
viously accumulated  nutriment,  under  the  influeuce  of 
oxidation.  The  common  European  broom-rapes  {Oro- 
hanchc)  have  no  green  leaves,  but  merely  pink,  purple, 
brown,  yellow,  blue,  or  rose-coloured  scales  and  flowers. 
Ci/tinus  hypocistis,  which  grows  parasitically  on  the  roots 
of  the  Cistus,  has  a  bright  orange  stem  and  leaves.  The 
common  English  dodder  is  noticeable  for  its  pretty  twining 
red  filaments,  while  its  Indian  congeners  display  brilliant 
hanging  masses  of  golden  threads.^  In  fact,  almost  all 
true  and  perfect  parasites  are  remarkable  for  the  absence 
of  green  and  the  presence  of  other  bright  hues.  Of  course, 
many  plants  usually  included  under  that  name,  like  the 
mistletoe  family,  have  foliage  of  the  ordinary  colour ;  but 
these  are  in  reality  only  half-parasitical,  a  kind  of  step- 
ping-stone between  the  epiphytic  plants  (orchids  and 
bromelias)  and  the  thorough-going  parasites,  such  as 
RaJJicsia.     To  the  very  end,  indeed,  the  degraded  leaves 

1  For  Drosera,  see  Darwin,    "In-    Drosophyllum,  p.  S33 ',  and  for  Pin- 
sectivorous  Plants,  '  or  any  English    guicula.  p.  391. 
moor;  for  Dioncea,  ibid.,  p.  287;  for        -  Hooker,  Himalayan  Journal,  pp. 

28,  38. 


52 


THE  COLOUR-SENSE. 


or  scales  of  flowering  plants  contain  some  traces  of  cliloro- 
phyll/  which,  however,  like  the  leaves  themselves,  must 
be  reo-arded  as  mere  obsolescent  relics  of  their  earlier 
state.  It  should  also  be  noticed  in  passing,  that  many 
parasites,  like  Rafflesia  and  Hydnora,  have  exceptionally 
larse  and  brilliant  flowers.  The  blossom  of  R.  Arnoldi 
sometimes  measures  three  feet  in  diameter. 

Still  more  noticeable  in  hue  are  the  plants  known  as 
saprophytes,  which  live  like  fungi  on  the  decaying  matter 
contained  in  dead  foliage  or  other  organic  remains.  These, 
too,  haA^e  no  real  assimilative  leaves,  while  their  functions 
are  purely  animal,  consisting  in  the  absorption  of  oxygen 
and  the  expenditure  of  previously  accumulated  energies. 
The  Indian-pipe  plant  of  Canada  (Monotropa  wiiflora) 
has  a  pure  w^hite  scaly  stem  and  flower,^  exactly  re- 
sembling a  fungus  to  the  untrained  eye ;  it  grows  under 
the  shade  of  pine  forests,  amid  the  rich  dShris  of  their 
pollen  and  their  fallen  foliage.  The  beautiful  Neottia 
speciosa  has  a  scape  and  rudimentary  leaves  of  bright 
scarlet.  CoraUorhiza  and  many  other  saprophytes  are 
equally  remarkable  for  their  exquisitely  coloured  scales. 
It  is  true  that  several,  if  not  all,  of  these  plants  contain 
small  quantities  of  chlorophyll  or  xanthophyll ;  ^  but  here 
again,  we  must  regard  the  pigment  as  a  mere  remnant 
of  earlier  ancestors  ;  while  the  plant,  as  a  whole,  mainly 
consists  of  metastatic  materials,  or,  in  other  words,  of 
oxidation  products. 

The  resemblance  which  both  parasites  and  saprophytes 
bear  to  fungi  is  certainly  remarkable  when  we  remember 
their  close  community  of  nature  and  function.  All  alike 
live  upon  previously  organised  material,  and  all  have  the 
same  flabby,  succulent,  pulpy  appearance.  The  Indian- 
pipe  plant  is  always  described  by  Canadian  farmers  as  "  a 
kind  of  toadstool ; "  the  Rafflesia  is  noted  for  its  fungoid 

1  "Wiesner,  Botan.  Zeitting,  1871,  as  differing  from  green,  must,  of 
p.  37,  quoted  in  Sachs,  643.  course,  be  accounted  a  colour. 

2  For  our  present  purpose,  white,        ^  Oscar  Drude,  "Biologie  von  Mo- 

notropa,"&c.,  Gottingen,  1873. 


INSECTS  AND  FLOWERS.  53 

look  and  animal  odour;  tlie  Cytinus  exhales  a  meaty 
flavour ;  and  the  Cynomormm  coccineum  is  known  to 
druggists  by  the  technical  name  of  Fungus  melitensis  or 
Malta  mushroom.  Putting  these  facts  by  the  side  of 
their  very  similar  colouration,  we  are  not  unnaturally  led 
to  expect  some  causal  connection  such  as  that  of  which 
we  are  now  in  search.  Let  us  pass  on  to  other  coloured 
portions  of  ordinary  plants,  which  may  throw  a  little  more 
light  upon  the  question  at  issue. 

Buds  contain  energetic  material,  stored  up  by  the  plant 
during  the  preceding  season,  and  expended,  presumably, 
by  union  with  oxygen,  during  the  spring.  The  sprouting 
buds  of  the  hawthorn  and  of  many  other  plants  present 
exquisite  tints  of  pink  and  mauve.  The  bulbils  of  the 
tiger-lily  are  covered  by  purple  scales.  The  various 
devices  by  which  plants  lay  by  nutriment  during  one 
season  for  their  growth  in  the  next  are  known  as  bulbs, 
tubers,  corms,  or  rhizomes.  All  of  these  are  apt  to  produce 
young  sprouts  of  dainty  colouring  and  bright  hue.  The 
growing  sprays  of  the  potato,  when  kept  carefully  from 
the  light,  exhibit  distinct  tinges  of  pink,  blue,  violet,  and 
yellow.  Asparagus  shoots  and  blanched  sea-kale  have 
scales  or  leaves  of  mauve,  lilac,  and  greenish  brown. 
Almost  all  bulbs,  on  first  producing  leaves,  show  very 
decided  colours,  which  change  to  green  under  the  action 
of  light.  Beet-root,  permitted  to  sprout  in  the  dark,  sends 
up  beautiful  bunches  of  deep  crimson  foliage.  Carrots, 
under  like  circumstances,  put  forth  golden  sprays,  varying 
from  light  primrose  to  bright  orange.  Sprouting  peonies 
are  of  a  full  dark  red.  Ehubarb  has  rosy  stems  and  pink 
or  yellow  leaves.  In  many  of  these  cases,  the  colour  is 
most  conspicuous  in  the  thin  laminated  portion  of  the 
young  leaves,  which  offer  the  best  medium  for  the  display 
of  delicate  pigments.  In  every  case,  exposure  to  the 
sunlight  brings  about  reversion  to  the  original  assimilative 
function,  and  results  in  the  final  triumph  of  green  chloro- 
phyll. 


54  THE  COLOUR-SENSE. 

The  young  shoots  at  the  end  of  branches  are  in  the 
same  position,  as  regards  energy,  with  the  sprouts  which 
arise  from  bulbs  or  tubers.  They  cannot  yet  feed  them- 
selves, but  they  are  nourished  by  energetic  materials  from 
the  older  leaves,  whose  carbon  combines  with  oxygen  in 
their  tissues  to  yield  the  energy  whereby  their  growth  is 
carried  on.  Kow  the  bright  tints  of  these  young  shoots 
are  very  noticeable  (as  may  be  especially  observed  in  the 
fuchsia,  the  hawthorn,  and  the  rose-apple),  and  they  can 
be  skilfully  arranged  in  such  combinations  as  to  produce 
a  visible  effect  not  at  all  unlike  that  of  flowers. 

If  we  compare  these  various  cases  with  those  of  bright- 
hued  entomophilous  blossoms  and  brilliant  fruits,  we 
shall  find  that  they  have  all  one  quality  in  common — 
they  occur  in  parts  which  are  expenders,  not  accumulators, 
of  energy.  Hence  we  are  led  to  suppose  that  those  por- 
tions of  plants  which  subsist  upon  previous  accumulations 
are  apt  to  assume  bright  hues  of  different  sorts.  To  what 
can  we  attribute  the  tendency  which  we  thus  observe  ? 
Can  we  give  any  causal  formula  for  the  empirical  general- 
isation at  which  we  have  now  arrived  ?  I  think  we  can, 
and  in  the  f  olio  win  cr  manner : — 

o 

Chlorophyll,  the  active  deoxidising  principle,  has  a 
definite  composition,  which  enables  it  to  carry  on  its 
proper  functions,  and  a  definite  mode  of  reflecting  light, 
which  we  call  green.  How  far  its  greenness  is  bound  up 
with  its  other  physical  properties  we  cannot  say.  Perhaps, 
as  has  been  objected,  it  might  equally  well  perform  its 
physiological  purpose  were  it  red  or  yellow.  But  more 
probably  its  special  reaction  upon  light  is  intimately  con- 
nected with  its  special  reaction  upon  carbonic  anhydride 
under  the  influence  of  light.  However  this  may  be,  at 
least  we  know  that  active  chlorophyll  is  ahvays  green ; 
and  the  more  active,  the  brighter  its  hue,  as  Mr.  Sorby 
has  abundantly  shown.  Hence,  every  part  of  a  plant 
which  performs  deoxidising  functions  has  necessarily  a 
green  pigment  for  its  foundation.     The  greenness  may 


INSE  CTS  A  ND  FL  0  WERS.  5  5 

indeed  be  masked  "by  other  dyes  (perhaps  themselves  the 
products  of  oxidation),  as  in  cell-sap  or  epidermis,  but  in 
the  actual  active  principle  itself,  greenness  is  apparently 
always  present  as  an  essential  and  inherent  property. 

So  leaves  as  a  rule,  where  exposed  to  sunlight,  are 
green,  but  the  remaining  portions  of  the  plant  do  not 
seem  to  be  bound  by  such  a  stringent  law  of  colouration. 
There  is  no  reason  why  other  colours  should  not  appear 
in  them  from  time  to  time,  and,  if  they  prove  useful,  be 
perpetuated  through  the  action  of  natural  selection.  How^, 
then,  do  they  arise  ? 

Colour,  we  have  seen  already,  is  merely  the  mode  in 
which  various  bodies  react  upon  light,  reflecting  or  ab- 
sorbing its  constituent  elements  in  varying  proportions 
of  their  several  rays.  But  there  is  no  property  of  different 
bodies  more  variable  in  its  nature  than  this  particular 
mode  of  reaction.  The  slightest  change  in  the  molecular 
constitution  of  a  substance  is  apt  to  be  accompanied  by 
considerable  changes  in  its  hue.  Materials  which  appear 
chemically  almost  identical  pass  through  strange  varieties 
of  tint  with  the  greatest  readiness.  And  this  is  particu- 
larly the  case  with  organic  matter,  which  differs  from  all 
other  matter  in  the  striking  effects  produced  upon  its 
physical  constitution  by  apparently  trifling  causes.  Hence 
we  might  naturally  expect  that  very  small  changes  in  the 
constituents  or  contents  of  plant  tissues  would  be  likely 
to  produce  great  alterations  in  their  colour.  And  we  find 
accordingly  in  all  non-active  parts  of  a  plant  that  by- 
products of  various  tints  do  actually  occur  wdth  consider- 
able frequency  :  take,  for  example,  the  bright  hues  of  many 
stems,  barks,  and  juices,  the  red  under-side  of  the  Victoria 
regia  leaf,  the  amber  nether  foliage  of  the  star-apple,  and 
the  beautiful  scales  of  the  gold  and  silver  ferns. 

Whether  such  colours  are  ahcays  due  to  oxidation, 
it  would  be  difficult  to  say ;  but  in  a  large  number  of 
instances  it  is  quite  clear  that  oxidation  is  going  on  in 
the  tissues  where  the  colours  appear.     Obviously,  in  all 


S6  THE  COLOUR-SENSE. 

cases  of  metastasis,  the  recombination  of  oxygen  with 
the  accumulated  hydrocarbons  is  the  only  source  of  the 
energy  whereby  growth  is  carried  on.  Sometimes  as  much 
as  40  or  even  50  per  cent,  by  weight  of  the  organic  matter 
contained  in  seeds  which  germinate  in  the  dark  is  lost  by 
conversion  into  carbonic  anhydride  and  water ;  1  and 
somewhat  the  same  change  must  take  place  in  bulbs, 
tubers,  corms,  and  rhizomes.  Almost  all  the  above- 
quoted  cases  fall  apparently  under  a  like  generalisation. 
The  red  colouring  matter  of  persistent  winter  leaves,  as 
seen  in  Sempervwum,  MaJionia,  Vaccinium,  and  Sedum,  is 
due  to  a  substance  mainly  consisting  of  tannin.^  Mr.  Sorby 
does  not  absolutely  say  that  the  colours  of  autumn  foliage 
are  due  to  oxidation,  but  he  refers  them  on  the  whole  to 
decreased  vitality,  absorption  of  chlorophyll,  and  similar 
causes,  which  bring  into  prominence  various  minor  prin- 
ciples otherwise  unnoticed.  Of  the  lychnoxanthine  series 
he  says  expressly,  "  They  are  probably  only  products  of  the 
oxidisation  of  chlorophyll,  from  which  they  may  be  pre- 
pared artificially."  Of  the  erythrophyll  series,  on  the 
other  hand,  he  merely  observes,  "  They  are  usually  indica- 
tive of  low  constructive  energy."  The  chrysotannin  group, 
again,  "  when  oxidised,  give  rise  to  various  brown  sub- 
stances, which  are  the  cause  of  many  of  the  characteristic 
tints  of  autumnal  foliage."  But  with  regard  to  the  pig- 
ments of  entomophilous  flowers  his  language  is  much 
more  decided  in  tone.  "  The  coloured  substances  in  the 
petals  are  in  many  cases  exactly  the  same  as  those  in  the 
foliage  from  which  chlorophyll  has  disappeared ;  so  that 
the  petals  are  often  exactly  like  leaves  which  have  turned 
yellow  or  red  in  autumn,  or  the  very  yellow  or  red  leaves 
of  early  spring.  ,  .  .  The  colour  of  many  crimson,  pink, 
and  red  flowers  is  due  to  the  development  of  substances 
belonging  to  the  erythrophyll  group,  and  not  unfrequently 
to  exactly  the  same  kind  as  that  so  often  found  in  leaves 
.  .  .  The  facts  seem  to  indicate  that  these  various  sub- 

1  Sachs,  uU  supra.  2  gaclis,  657. 


INSECTS  AND  FLOWERS.  57 

stances  may  be  due  to  an  alteration  of  the  normal  con- 
stituents of  leaves,  some  being  probably  formed  from 
chloropliyll,  others  from  the  xanthophylls,  and  perhaps 
some  from  other  constituents.  So  far  as  I  have  been  able 
to  ascertain,  their  development  seems  as  if  related  to  extra 
oxidisation,  modified  by  light  and  other  varying  conditions 
not  yet  understood."  ^  In  like  manner  Lory  found  that 
parasites,  as  exemplified  by  broom-rapes,  absorbed  oxygen 
and  exhaled  carbonic  anhydride  in  all  stages  of  growth, 
whether  exposed  to  the  sun  or  not.^  So,  also,  Morot 
showed  that  in  etiolated  plants  the  coloured  portion  of 
the  tissues  gave  out  carbonic  anhydride,  while  the  green 
portion  gave  out  oxygen.^  In  short,  without  going  into 
the  lengthy  ultimate  question — scarcely  soluble  at  present 
— whether  all  bright  vegetal  pigments  (except  chloro- 
phyll) are  themselves  actually  oxidation  products,  we 
may  at  least  affirm  that  they  occur  with  exceptional 
frequency  in  those  plants  or  parts  of  plants  where  oxida- 
tion is  largely  taking  place.  They  may  be  always  directly 
due  to  the  absorption  of  oxygen,  or  they  may  be  merely 
secondary  results  of  that  action ;  but  they  certainly  show 
a  great  tendency  to  present  themselves  wherever  energy 
is  being  expended ;  and  that  conclusion  is  quite  sufficient 
for  our  immediate  object. 

Here,  to  guard  against  an  obvious  criticism,  it  should  be 
added  that  only  a  tendency,  not  a  universal  law,  in  such 
a  direction  is  believed  to  exist.  For  example,  the  leaves 
of  the  sensitive  plant  and  the  Desmodiicm,  which  exhibit 
movements  far  more  marked  than  those  of  the  insectivo- 
rous species  already  noticed,  are  perfectly  green.*     But  the 

1  Proc,  Koy.  Soc,  vol.  xxi.  p.  478.  the  materials  for  this  chapter  when 

2  Annales  des  Sciences  Nat.,  3ine  in  manuscript.  Professor  Thiselton 
Ser.  Botanique,  viii.  158.  Dyer  also  supplied  me  with  many  use- 

3  Balfour,  Class-Book  of  Botany,  ful  notes  in  connection  with  this  sub- 
p.  473.  ject,  of  which  I  have  gladly  availed 

^  My  thanks  for  calling  attention  to  myself.     At  the  same  time,  I  ought 

this  exception  are  due  to  Mr.  Darwin,  to  mention  that  although  I.  have  al- 

who  kindly  favoured  me  with  several  tered  much  of  my  original  matter  in 

valuable  critical    observations    upon  accordance  with  objections  raised  by 


58  THE  COLOUR-SENSE. 

Avliole  conclusion  here  suggested  amounts  in  brief  to  the 
following  principle  :  Wherever  considerable  changes  occur 
in  the  nature  of  the  vegetal  tissues  or  their  contents,  they 
are  apt  to  be  accompanied  by  similar  changes  in  the  re- 
action of  the  tissues  upon  the  incident  sunbeams. 

Yet  it  is  a  noteworthy  fact  of  great  importance,  as  shed- 
ding light  upon  the  origin  of  the  colour-sense,  that  such 
brilliant  tints  are  everywhere  exceptionally  common  in 
the  organic  world.  Besides  the  green  of  chlorophyll,  the 
orange  and  scarlet  of  autumn  leaves,  or  the  varied  hues  of 
flowers  and  fruits,  we  find  unusually  bright  colouring  in 
many  parts  of  animals,  especially  the  very  simplest,  such 
as  jellyfish  and  sea-anemones.  Although,  as  we  shall 
observe  hereafter,  many  of  these  are  doubtless  due  to  the 
selective  action  of  sexual  preference,  acting  through  the 
colour-sense  itself,  yet  in  the  lowest  organisms  there  is 
some  reason  to  believe  that  the  purity  and  splendour  of 
the  prevailing  hues  are  only  due  to  the  adventitious  com- 
position of  their  molecules.  And  when  we  further  notice 
the  brightness  of  mammalian  blood,  besides  the  numerous 
changeful  hues  of  sundry  viscera  or  their  contents,  we  shall 
probably  be  willing  to  allow  that  organic  bodies  habitually 
display  pure  and  gorgeous  tints,  which  the  mineral  w^orld 
only  shows  us  in  a  few  rare  and  exceptional  jewels. 

Before  we  proceed,  however,  to  apply  these  general 
principles  to  the  genesis  of  entomophilous  flowers,  it  will 
be  well  to  glance  briefly  at  a  distinction  of  considerable 
importance,  already  hinted  at  in  the  preceding  paragraph. 
Colour,  as  such,  cannot  of  itself  subserve  any  special  func- 
tion except  in  connection  with  the  animal  eye.  The  hues 
of  all  inorganic  and  of  most  organic  bodies  depend  entirely 
upon  the  fortuitous  molecular  constitution  of  the  parti- 
cular body.  But  when  a  colour  so  reflected  happens  to 
produce  some  specific  effect  upon  the  eyes  of  any  animal, 

tliese  distinguislied  naturalists,  they  many  of  which  Professor  Dyer,  at 
are  not  in  anyway  responsible  for  any  least,  would  dissent  in  the  most  uu- 
of  the  statements  here  made,  from    equivocal  manner. 


INSECTS  AND  FLOWERS.  59 

■whose  interference  is  either  useful  or  noxious  to  the  ani- 
mal or  plant  reflecting  it,  then  the  principle  of  natural 
selection  will  come  into  play,  and  the  colour,  as  such,  may 
be  said  to  subserve  the  special  function  of  attraction  or 
protection,  as  the  case  may  be.  Henceforward,  in  the 
present  w^ork,  a  colour  which  seems  simply  to  depend  upon 
molecular  constitution,  apart  from  function  to  be  subserved, 
will  be  described  as  adventitious  ;  w^hile  a  colour  which 
also  subserves  a  special  function  will  be  described  as 
'piiT'posive: 

Now  all  the  coloured  objects  with  which  we  have  so  far 
dealt — green  leaves,  autumn  foliage,  young  shoots,  sprout- 
ing buds — are  purely  adventitious  in  their  tints.  Flowers, 
however,  which  we  next  approach,  are  purposive;  but, 
like  all  other  purposive  adaptations,  they  must  neces- 
sarily have  taken  their  rise  in  some  adventitious  circum- 
stance, after^vards  increased  and  developed  by  selective 
action. 

With  such  data  before  us,  then,  let  us  proceed  to  inquire 
what  was  the  genesis  of  those  bright  entomophilous 
flowers,  which  present  brilliant  tints  in  specialised  thin 
leaves  or  petals,  admirably  adapted  alike  for  rapid 
oxidation,  and  for  the  ostentatious  display  of  delicate 
pigments. 

The  flower  is  one  of  the  purely  expensive  structures 
which  we  noticed  above  as  seats  of  oxidation  and  liberated 
energy.  The  well-known  experiments  of  Saussure,  Du- 
trochet,  Vrolik,  and  De  Vriese,  detailed  in  all  handbooks 
of  physiological  botany,  sufficiently  prove  that  during  the 
act  of  flowering  oxygen  is  consumed,  carbonic  anhydride 
evolved,  and  heat  liberated.  These  experiments  have  been 
generally  conducted  upon  various  species  of  Arum,  which 
are  insect-fertilised  flowers  ;  but  similar  phenomena  have 
also  been  observed  in  the  cones  of  cycads,  whose  blossoms 
are  strictly  anemophilous.  Indeed,  as  the  absorption  of 
oxygen  is  chiefly  concerned  with  the  maturation  of  the 
pollen,  and,  to   a  less  extent,  of   the  pistil,  it   is  clear 


6o  THE  COLOUR-SENSE. 

that  it  can  be  but  little  influenced  by  the  nature  of  tlie 
surroundiiiGf  structures. 

o 

Hence  we  would  naturally  expect  that  all  floral  organs, 
wind-fertilised  or  insect-fertilised  alike,  would  show  a 
tendency  to  the  production  of  bright  colours,  in  accord- 
ance with  the  general  princii)le  here  laid  down.  This  a 
^priori  expectation  is  fully  justified  by  the  actual  facts. 

In  the  first  place,  even  among  flowerless  plants,  the 
purely  expensive  structures  employed  in  the  elaboration 
of  young  spores  are  almost  always  tinged  with  some  other 
hue  than  that  of  the  green  pigment  which  distinguishes 
the  active  and  assimilating  leaves.  In  mosses  the  grace- 
ful little  spore-cases,  which  rise  like  miniature  fruits  at 
the  extremity  of  the  tall  spiky  stems,  are  usually  pink  or 
reddish  brown  in  colour.  The  beautiful  SplacJmum  ruhrum 
of  the  Canadian  forests  has  a  cup  of  brilliant  scarlet,  which 
has  led  the  children  who  pick  it  to  give  it  the  pretty 
popular  name  of  red-cap  moss.  Many  lycopodiums  pro- 
duce bright  golden  fructifications,  very  conspicuous  in  the 
lovely  exotic  L.  dendroideum.  Ferns  generally  bear  their 
spores  on  the  under  surface  of  the  frond,  where  their 
brown  or  russet  colour  makes  them  very  noticeable  and 
pretty  objects.  So  that,  in  spite  of  their  ill-chosen  name, 
the  cryptogams  themselves  exhibit  the  universal  tendency 
to  varied  colouration  in  the  reproductive  organs. 

I^ext,  when  we  examine  the  phanerogamous  division  of 
plants,  we  see  at  once  that  the  actual  floral  structures 
themselves  are  always  more  or  less  marked  by  distinctive 
colours.  The  pollen  is  generally  of  a  rich  golden  yellow, 
while  the  surrounding  scales  show  tints  of  silvery  grey  or 
faint  pink.  Even  among  the  wind-fertilised  blossoms,  not 
a  few  are  thus  rendered  conspicuous  when  they  hang 
thickly  together  in  large  close-set  masses.  Many  catkins, 
several  grasses,  the  larch  and  other  conifers,  the  dock  and 
its  congeners,  all  display  blossoms  of  considerable  distinc- 
ness,  quite  uninfluenced  by  the  selection  of  insects.  The 
inner  bracts  of  the  unopened  artichoke  head  are  often  a 


INSECTS  AND  FLOWERS.  6i 

brilKant  mauve,  not  less  beautiful  than  that  of  many 
flowers.  The  glumes  which  surround  the  floral  organs  of 
grasses  are  ruddy  purple.  The  female  flowers  of  the  com- 
mon hazel  are  a  fine  red,  as  Mr.  Darwin  reminds  me. 
Evidently  we  have  here  a  groundwork  of  differential 
colouring  upon  which  selection  might  set  to  work,  and 
ultimately  produce  the  striking  results  that  we  see  to-day 
in  every  flower-garden. 

These,  then,  are  the  ultimate  elements  of  our  problem, 
riowers  consist  essentially  of  male  and  female  organs, 
which  really  represent  aborted  leaves,  greatly  modified  for 
their  special  function,  as  Wolff  and  Goethe  long  since 
pointed  out.  These  reproductive  organs  are  situated  at 
the  ends  of  axes,  where  growth  is  failing ;  and  Mr.  Herbert 
Spencer  observes  that  such  points  are  just  the  ones  where 
coloured  leaves,  as  noted  above,  frequently  make  their 
appearance.^  In  anemophilous  flowers,  as  a  rule,  we  find 
only  the  two  whorls  of  essential  floral  organs ;  but  in 
entomophilous  flowers,  as  a  rule,  we  find  two  additional 
whorls,  the  petals  and  the  sepals,  one  or  both  of  which  are 
brilliantly  coloured,  the  colouration  apparently  subserving 
no  other  purpose  than  the  attraction  of  insects  who  aid  in 
fertilising  the  flowers.  We  can  hardly  resist  the  inference 
that  the  coloured  whorls  represent  an  intensification  of 
the  natural  tint  in  growing  shoots  and  floral  organs,  slowly 
modified  by  the  selective  action  of  the  insect  eye. 

When  we  look  more  closely  at  the  nature  of  showy 
entomophilous  flowers,  this  conviction  becomes  greatly 
strengthened.  If  colouration  depends  wholly  or  in  part 
upon  oxidation  of  previously  stored  material,  it  will  follow 
that  very  large  and  massive  blossoms  can  only  be  produced 
by  the  aid  of  considerable  prior  accumulations  in  some 
portion  of  the  parent  plant.  Now  this  is  exactly  what 
we  find  to  be  the  case  in  nature.     Most  very  big  flowers 

1  Principles    of    Biology,    ii.    249,    but  vigorously  sketched  out  in  a  few 
■where  the  whole  question  treated  in    pages, 
detail  in  this  chapter  has  been  rapidly 


62  .      THE  COLOUR-SENSE. 

depend  for  their  support  upon  bulbs,  corms,  tubers,  or  other 
like  bulky  reservoirs  of  energetic  material.  It  will  be 
sufficient  to  mention  the  cases  of  the  waterlilies,  the 
lotus,  the  dahlias,  the  orchids,  the  iris,  the  crocus,  the 
gladiolus,  the  narcissus,  the  snowdrop,  the  daffodil,  the 
tulip,  the  various  lilies,  the  tuberose,  the  hyacinth,  and  the 
meadow-saffron.  In  many  of  these  plants  the  handsomest 
heads  of  bloom  are  secured  by  cutting  off  the  flower-buds 
for  several  successive  years,  and  so  preventing  the  expen- 
diture of  material  until  enough  has  been  accumulated  for 
a  gorgeous  display  of  blossom.  Certain  other  flowers, 
again,  depend  for  support  upon  starch  or  other  nutriment 
laid  by  in  the  fleshy  receptacle  from  which  they  spring. 
This  is  the  case  with  the  artichoke,  the  dandelion,  and 
many  of  their  sister  composites.  A  third  class  lives  upon 
materials  stored  up  in  the  woody  branches,  as  in  the 
almonds,  flowering  cherries,  and  other  trees,  which  bloom 
in  the  spring  before  the  fresh  leaves  make  their  appear- 
ance. Yet  a  fourth  sort  maintain  themselves  cheaply 
upon  the  manufactured  juices  of  other  plants,  like  the 
leafless  parasite,  Eafflesia,  whose  flower  measures  three 
feet  in  diameter,  or  the  pretty  little  English  dodder,  whose 
suckers  fasten  themselves  tightly  upon  the  growing  stems 
of  gorse.  A  great  number  of  the  most  beautiful  exotics 
are  saprophytes,  which  live  entirely  upon  the  decaying 
vegetable  mould  in  which  they  are  embedded.  Indeed, 
whenever  showy  flowers,  like  poppies  and  convolvulus, 
grow  without  the  aid  of  some  such  accumulated  nutri- 
ment, it  will  generally  be  found  that  their  petals  are  thin 
and  papery,  so  that  the  total  cubical  content  of  the  flower- 
bud  is  really  quite  inconsiderable.  Such  plants,  in  fact, 
have  learnt  to  make  a  very  great  display  at  very  little 
actual  expense. 

Furthermore,  flowers  often  exhibit  different  colours 
according  to  the  state  of  oxygenation  which  their  juices 
have  reached,  and  these  differences,  as  I  shall  endeavour 
to  show  hereafter,  bear  a  definite  relation  to  the  various 


INSECTS  AND  FLOWERS.  63 

periods  of  maturity,  and  tlie  particular  insect  whose 
assistance  is  required.  Almost  all  blossoms  in  their  early 
stages  contain  green  pigments  and  perform  foliar  func- 
tions ;  but  as  they  mature,  they  gradually  assume  their 
proper  hues  of  yellow,  blue,  or  red.  "  The  endochrome  of 
the  rudimentary  petals,"  says  Mr.  Sorby,^  "  approximates 
in  character  to  that  of  the  leaves ;  and,  during  their 
development,  their  leaf-like  character  is  gradually  lost, 
and  often  new  colouring  matters  are  formed."  The  series 
of  changes  may  be  easily  followed  in  a  hyacinth,  a  tulip, 
or  a  daffodil ;  but  perhaps  the  garden  hydrangea  {H.  hor- 
tensis)  offers  the  best  opportunity  for  watching  this  inte- 
resting phenomenon,  because  the  structures  in  which  the 
mauve  or  pink  pigment  finally  appears  are  exposed  to 
view  during  the  whole  process  of  maturation.  Other 
changes  also  frequently  take  place  after  the  flower  is  fully 
developed.  "  CheirantJius  chamcdeo  has  at  first  a  whitish 
flower,  then  a  citron-yellow,  then  red  or  slightly  violet ; 
the  petals  of  StylicUum  friiticosum  are  pale  yellow  at  first, 
then  lightish  rose-coloured ;  the  flowers  of  CEiiotliera  tetra- 
ptera  are  first  whitish,  than  rose-coloured  or  nearly  red ; 
the  corolla  of  Cobcca  scanclens  is  greenish-white  the  first 
day,  and  violet  the  day  following ;  the  flowers  of  Hibiscus 
mutahilis  appear  in  the  morning  of  a  white  colour,  towards 
midday  they  become  flesh-coloured,  and  at  night  they 
are  red."  ^  F.  MuUer  has  observed  a  Lantana  at  Sta. 
Catherina  in  Brazil,  the  flowers  of  which  last  three  days, 
"  being  yellow  on  the  first,  orange  on  the  second,  purple 
on  the  third  day ; "  ^  and  his  interesting  explanation  of 
this  peculiarity  will  find  further  mention  when  we  come 
to  treat  of  the  parallel  adaptation  whereby  insects  have 
accommodated  themselves  to  the  colours  of  flowers.  In- 
deed, Delpino  believes  that  all  such  changes  of  hue  are 
specially  intended  to  inform  the  fertilising  insects  of  the 
proper  moment  for  efi'ecting  impregnation. 

1  Quarterly    Journal    of    Science,         "  Balfour,  p.  541. 
1873,  p.  463.  3  "Nature,"  November  29,  1877. 


64  THE  COLOUR-SENSE. 

We  conclude,  tlien,  with  much  probability,  that  the 
bright  pigments  of  entomophilous  plants  are  due  origin- 
ally to  the  natural  oxidation  taking  place  in  all  purely 
expensive  structures,  aided  by  the  selective  action  of 
insects.  It  is  noteworthy,  as  proving  the  functional 
origin  of  these  pigments,  that  both  great  divisions  of 
flowering  plants,  the  monocotyledons  and  the  dicotyledons, 
have  independently  hit  upon  the  very  same  device  of 
coloured  leaves  for  attracting  their  insect  allies.  But 
this  could  hardly  have  happened  had  not  some  original 
groundwork  existed  in  the  mere  fact  of  oxidation,  upon 
which  selective  action  might  be  successfully  exerted. 
Still  more  clear  does  this  argument  become  when  we 
recollect  that  in  almost  every  family  under  these  two 
great  divisions,  anemophilous  and  entomophilous  genera 
may  be  found  side  by  side,  thus  proving  that  the  device 
of  colour  has  been  independently  adopted  by  different 
plants,  not  twice  alone,  but  a  thousand  times  over.  When- 
ever brilliant  leaves  showed  any  tendency  to  appear  in 
the  neighbourhood  of  the  floral  organs,  no  matter  what 
the  species,  genus,  family,  or  class,  it  would  seem  that  the 
plant  thereby  derived  such  an  advantage  as  to  perpe- 
tuate the  habit  in  future,  under  the  constant  stimulus  of 
over-population  and  natural  selection,  resulting  in  survival 
of  the  fittest. 

When  we  pass  on  to  examine  the  various  parts  of  the 
flower  which  may  thus  become  devoted  to  the  attractive 
function,  we  find  still  plainer  evidence  to  the  same  eftect. 
The  essential  floral  organs  themselves,  already  so  conspi- 
cuous in  the  various  catkins,  may  be  specially  modified 
for  the  sake  of  displaying  brilliant  pigments.  The  com- 
mon meadow  rue  depends  almost  entirely  for  attraction 
upon  these  organs.  In  the  family  of  Mesembryanthe- 
mums,  the  outer  stamens  become  flattened  and  petaloid, 
so  as  to  resemble  the  corolla  of  ordinary  flowers.  In  the 
waterlilies,  the  tendency  towards  a  similar  change  is 
always  noticeable.     Indeed,  if  one  may  hazard  a  guess  in 


INSECTS  AND  FLOWERS.  65 

SO  uncertain  a  question,  analogy  would  rather  lead  us  to 
suppose  that  all  petals  are  modified  stamens  than  that 
the  transition  has  taken  place  in  the  opposite  direction. 
However  this  may  he,  the  corolla,  or  petaline  whorl,  forms 
in  most  flowers  the  main  attractive  orc^an.  Eoses,  butter- 
cups,  violets,  bluebells,  and  primroses  may  stand  as  suffi- 
cient examples.  Next  in  order  comes  the  calyx,  or 
sepaline  whorl,  usually  a  protective  organ,  but  often  so 
modified  as  to  aid  in  the  function  of  alluring  the  insect 
guests.  In  the  fuchsia,  the  bright  sepals  make  the  most 
striking  part  of  the  whole  blossom;  while  in  the  tulip, 
crocus,  and  other  brilliant  monocotyledonous  plants,  both 
sepals  and  petals  are  coloured  alike,  so  as  to  be  usually 
lumped  together  under  the  common  name  of  perianth 
pieces.  In  the  marsh  marigold,  the  marvel  of  Peru,  the 
purple  clematis,  and  the  crimson  Aristolocliia  cordata,  the 
petals  are  wholly  wanting,  and  the  calyx  alone  performs 
the  task  of  ostentatious  chromatic  display. 

Nor  does  the  process  of  colouration  stop  short  at  the 
regular  floral  whorls.  The  bracts  and  other  secondary 
adjuncts  often  aid  in  the  attractive  effect.  Several 
euphorbias  have  separately  inconspicuous  flowers,  enclosed 
in  a  common  involucre  of  the  most  beautiful  scarlet  hue. 
Foinsettia  pulcherrima  bears  tiny  yellow  blossoms,  which 
would  doubtless  fail  by  themselves  to  catch  even  the 
microscopic  eye  of  a  tropical  butterfly;  but  they  are  sur- 
rounded by  a  thick  mass  of  gorgeous  crimson  bracts,  so 
strikingly  lovely  as  to  ensure  for  the  plant  a  place  in  all 
our  great  conservatories.  The  various  arums  bear  their 
minute  flowers  on  a  yellow  spadix,  about  which  grows  a 
huge  white  or  purply-green  sheath,  known  as  a  spathe, 
whose  large  size  and  bright  colour  makes  up  for  the  rela- 
tive inconspicuousness  of  the  essential  organs.  In  short, 
whatever  part  happened  to  display  a  tendency  towards 
bright  colouration,  and  thereby  attracted  the  attention  of 
insects,  would  naturally  grow  more  and  more  prominent 


66  THE  COLOUR-SENSE. 

from  generation  to  generation,  till  it  readied  the  furthest 
limit  of  useful  expenditure.^ 

That  the  colour  of  the  flower  is  a  mere  intensification 
of  that  prevailing  in  the  stem  has  long  since  been  recog- 
nised by  painters.  In  some  cases,  as  in  Peperomia,  the 
hue  of  the  stem  becomes  itself  very  noticeable.  In 
others,  as  in  Echeveria,  the  stalk  and  bracts  are  pinkish, 
gradually  growing  deeper  till  we  reach  the  calyx,  while 
the  petals  themselves  appear  simply  as  an  intensified  form 
of  the  surrounding  tint.  In  Epiphyllums,  the  end  of  the 
leaf -like  peduncle  is  often  bright  red  like  the  blossom 
itself.  Amongst  English  plants,  Ecliium,  Sedum,  Chryso- 
splenmm,  Rumex,  and  many  other  genera,  show  like  pheno- 
mena. And  when,  as  in  the  parasites  and  saprophytes, 
the  stem  and  scales  have  no  special  reason  for  greenness, 
we  find  such  brilliant  examples  as  Lastrma,  Monotropa, 
Neottia,  and  Corallorhiza,  whose  rudimentary  leaves  are 
quite  as  beautifully  coloured  as  the  flowers  themselves. 

From  whatever  point  of  view  we  regard  the  question, 
then,  it  seems  equally  probable  that  even  before  insect 
selection  had  come  into  play  certain  flowers  would  show 
a  considerable  tendency  to  the  production  of  adventitious 
colours.  Wherever  such  patches  of  red  or  blue  shone  out 
among  the  prevailing  green  of  primitive  forests,  we  may 
be  sure  they  would  act  as  beacons  to  the  rudimentary  eyes 
of  unspecialised  insects.  At  first  their  colours  would 
doubtless  be  arranged  in  very  indefinite  patches ;  but  as 
they  were  gradually  selected  by  their  insect  visitors,  the 
effects  of  cross-fertilisation,  by  weeding  out  individual 
peculiarities,  would  make  their  shape  and  hue  more  and 
more  definite  with  .each  new  generation.  For  such  defi- 
niteness,  as  we  shall  observe  abundantly  hereafter,  is  a 

^  I  was  once  given  a  pine-apple  in  liarity     had    proved    \iseful    to    the 

Jamaica   by    a  negro    cottager,    the  plant,  instead  of  hurtful,  as  it  really 

crest  or  empty  bracts  of  which  liad  was,  it  might  have  originated  a  per- 

assumed   a  bright  scarlet    hue,  like  manent  variety,     Tlie  garden  cocks- 

thtit  oi  so  many  Bromelice,  while  the  comb  {Ceiosia  cristata)  is  an  instance 

succulent  mass  beneath  had  become  of  such  a  monstrosity  carefully  pre- 

dry   and  shrivelled.      If  this  pecu-  served  by  artificial  selection. 


INSECTS  AND  FLOWERS.  67 

mark  of  contradistinction  between  adventitious  and 
purposive  colouration.  Wherever  we  find  a  plant,  like 
the  common  West  Indian  Bromelia  pinguin,  in  which  the 
spathes  are  coloured  brightly  but  irregularly,  the  crimson 
fading  off  into  white  or  green,  we  may  fairly  conclude 
that  the  selective  process  has  not  yet  proceeded  very  far. 
But  when  we  get  a  definite  bunch  of  crimson  bracts,  as  in 
Poinsettia  'pulchciTima,  standing  apart  as  a  regular  mass 
from  the  green  foliage  below,  we  may  be  sure  that  the 
selective  process  has  continued  for  a  considerable  period 
of  time ;  while  in  the  three  constant  coloured  leaves  which 
surround  the  little  blossoms  of  the  Bougainvillea,  we  see  a 
still  further  progress  in  numerical  definiteness.  So,  too, 
if  we  compare  the  English  cuckoo-pint  with  the  Ethio- 
pian lily  {Richardia  africana),  or  the  apple  with  the 
orange,  we  shall  see  reason  to  believe  that  the  former  cases 
represent  a  relatively  incomplete,  and  the  latter  cases  a 
relatively  complete,  stage  of  the  differentiating  action.  And 
we  shall  observe  hereafter,  when  we  come  to  examine  the 
origin  of  bright-coloured  fruits,  that  these  structures, 
which  have  been  developed  to  suit  the  eyes  of  birds  and 
mammals,  and  are  therefore  comparatively  late  in  geolo- 
gical time,  possess  on  the  whole  much  less  definite  colours 
than  entomophilous  flowers,  which  have  been  developed 
to  suit  the  eyes  of  insects,  and  date  far  back  in  geological 
time. 

The  first  step  towards  definiteness  in  colouration  is 
gained  by  that  dwarfing  of  the  internodes  which  gives  the 
floral  whorls  their  circular  appearance.  The  earliest  ento- 
mophilous flowers  probably  belonged  to  the  dicotyledonous 
group,  which  now  exhibits  the  highest  differentiation  of 
any ;  but  they  consisted  of  separate  petals,  like  the  com- 
mon dog-rose,  instead  of  being  tubular  or  bell-shaped,  like 
the  honeysuckle  or  the  campanula.^     Gradually,  however, 


1  J.  E.Taylor,  F.G.S.,  "  Geologi-  ary  1878.  I  cannot  agree  witli  Mr. 
cal  Antiquity  of  Insects  anil  Flowers,"  Taylor,  however,  in  supposing  that 
in  "Popular  Science  Review,"  Janu-    entomophilous  monocotyledons  pre- 


68  THE  COLOUR-SENSE. 

the  various  petals  in  certain  cases  became  adnate,  that  is 
to  say,  developed  together,  so  as  to  form  a  single  indented 
corolla.  The  former  class  of  flowers  are  known  as  ipoly- 
petalous,  the  other  as  ganwpdalous.  At  a  still  later  date 
came  the  irregular  flowers,  like  the  labiates  and  orchids, 
which  are  specially  adapted  to  the  shapes  of  insects; 
while  the  differentiating  process  is  doubtless  still  going 
on  under  our  very  eyes  whenever  a  bee  visits  a  blossom  in 
the  meadows  around  us. 

Side  by  side  with  this  differentiation  of  various  flowers 
went  the  differentiation  of  flower-haunting  insects.  Even 
in  the  Carboniferous  w^orld  some  vagrant  species  of  that 
great  class  already  lived  in  the  hard  siliceous  underbrush ; 
but  Sir  John  Lubbock  believes  that  Hym.enoptera,  Hemip- 
tera,  and  Diptera  first  came  into  being  during  the  Cre- 
taceous era;  while  Lepidoptera,  or  butterflies,  did  not 
appear  until  the  Tertiary  times.  Beetles  first  exhibit 
evident  marks  of  flower-feeding  during  the  Miocene  epoch. 
As  for  honey-bees,  they  probably  represent  the  very  latest 
and  most  highly  differentiated  members  of  the  whole  class, 
and  they  could  hardly  have  reached  their  present  form  till 
a  very  late  period.  In  short,  if  we  look  at  the  correlation 
of  the  flowers  and  the  insects,  we  shall  see  reason  to  be- 
lieve, what  is  already  suspected  on  purely  palseontological 
grounds,  that  gamopetalous  flowers  could  not  be  developed 
before  the  rise  of  specialised  insects  having  a  proper  pro- 
boscis fitted  for  fertilising  their  bloom. 

Again,  the  entomophilous  monocotyledons  are  probably 
far  more  modern  in  date  than  the  bright-coloured  dicoty- 
ledons, and  they  are  also  on  the  wdiole  far  more  leaflike 
and  less  definite.  Most  of  them  consist  of  six  perianth 
pieces,  shaped  very  much  like  the  ordinary  leaves,  and 
seldom  having  any  specialised  features.  Yet,  as  they 
found  the  field  already  occupied  by  bright-hued  dicotyle- 

ceded  similar  dicotyledoas.     All  the  plants  counts  for  very  little,  as  their 

structural  indications   point    in   the  earliest  species  may  very  well   have 

opposite  direction  ;  and  the  mere  fact  been  anemophilous. 
cf  the  early  appearance  of  liliaceous 


INSECTS  AND  FLOWERS,  69 

dons,  it  was  necessary,  if  they  would  secure  the  attention 
of  insects,  to  bid  for  their  favour  by  very  large  and  showy 
blossoms.  Accordingly,  these  newest  comers  amongst  the 
insect-fertilised  plants  form  a  large  proportion  of  our 
choicest  garden  species.  It  will  suffice  merely  to  enume- 
rate the  iris,  crocus,  narcissus,  daffodil,  snowdrop,  ama- 
ryllis,  aloe,  tulip,  tiger -lily,  fritillary,  crown -imperial, 
tuberose,  hyacinth,  star  of  Bethlehem,  meadow-saffron, 
hellebore,  arum,  and  Ethiopian  lily,  to  show  how  many 
of  the  most  brilliant  flowers  belong  to  this  class.  Even 
here,  however,  a  large  number  of  species  have  advanced 
to  a  high  degree  of  differentiation,  due  to  the  agency  of 
insects.  While  many  lilies  have  six  separate  perianth 
pieces,  as  we  see  in  the  tulip  and  the  fritillary,  others,  like 
the  lily  of  the  valley,  have  become  quite  gamopetalous,  or, 
to  speak  more  correctly,  the  petaline  and  sepaline  whorls 
have  coalesced  into  a  bell-shaped  cup.  But  the  orchid 
family  display  the  most  curious  adaptations  of  all,  being 
modified  in  an  infinite  variety  of  ways  to  suit  the  insects 
of  their  several  countries,  and  presenting  the  most  mar- 
vellous tricks  of  mimicry,  mechanical  device,  and  sportive 
cunning,  which  at  first  sight  almost  compel  us  to  imagine 
an  inherent  consciousness  guiding  the  blind  course  of  their 
strange  developments.^ 

It  has  been  remarked,  too,  that,  as  a  rule,  flowers  whose 
forms  are  highly  modified,  so  as  to  admit  of  fertilisation 
with  considerable  certaint}^  by  a  single  insect  visitor,  do 
not  need  the  same  large  display  of  showy  corollas  as  those 
which  trust  almost  to  chance  for  the  conveyance  of  their 
pollen  to  the  proper  receptacle.  Thus  Sprengel  contrasts 
the  great  size  and  numerous  petals  of  the  water  lily,  whose 
shape  has  no  special  reference  to  the  organs  of  the  ferti- 
lising insect,  with  the  little  labiates,  whose  form  ensures 
the  due  application  of  the  pollen  at  every  visit.^  So,  too, 
we  may  compare  the  common  orchid  with  the  fritillary, 

1  See  Darwin, ''Fertilisation  of  Or-        ^  Lubbock,   "British  Wildflowers, 
chids,"  passim.  in  tbeir  Kelation  to  Insects,"  p.  55. 


70  THE  COLOUR-SENSE. 

tlie  lily  of  the  valley  with  the  tulip,  and  the  composites 
with  the  rose  family.  Of  course  many  interfering  causes 
must  be  understood  as  putting  a  limitation  upon  the  truth 
of  this  roughly  generalised  statement.  For  example, 
the  great  tropical  butterflies,  the  larger  bees,  and  the  hum- 
ming-birds, form  fertilising  agents  who  naturally  demand 
large  masses  of  colour  as  an  attraction;  or,  again,  the 
presence  of  scent,  honey,  or  other  special  allurements,  may 
make  up  in  particular  cases  for  the  lack  of  bright  corollas. 
Yet,  on  the  whole,  it  may  be  said  that,  other  things  equal, 
high  modification  in  form  is  accompanied  by  a  decreased 
expenditure  on  coloured  adjuncts. 

Nor  is  it  only  in  the  shape  and  colour  of  individual 
flowers  that  plants  vie  with  one  another  for  the  favours  of 
their  insect  guests.  Like  varieties  are  also  to  be  found  in 
the  mode  of  massing  the  blossoms  so  as  to  attract  from  a 
great  distance  the  eyes  of  passing  bees  or  butterflies.  We 
must  remember  that  the  facets  of  the  articulate  visual 
organ  are  not  adapted  for  perceiving  small  objects  except 
at  a  comparatively  close  range.^  Hence  those  plants 
which  can  group  their  several  blossoms  into  large  and 
conspicuous  bunches  may  derive  special  advantages  from 
the  extra  attractiveness  thus  attained.  Such  species  a^ 
the  peony  or  the  tulip  bear  a  single  terminal  blossom  at 
the  end  of  their  stalk.  Others,  like  the  pimpernel  or 
the  veronica,  have  a  few  tiny  flowers  half  hidden  at  the 
axes  of  the  leaves.  But  the  hyacinth,  the  laburnum,  and 
the  lilac,  group  their  bloom  into  large  upright  or  hang- 
ing masses ;  while  the  cowslip,  the  carrot,  and  the  cal- 
ceolaria produce  flattened  heads  which  strike  the  eye 
from  a  considerable  distance.  The  dog-rose,  with  its 
scattered  flowers,  does  not  catch  our  passing  glance  so 
readily  as  the  apple-tree  or  the  may  ;  and  the  great 
tropical  flowering  forest  trees  may  often  be  discerned  by 

^  See  Mr.  Lowne's  paper  "On  the     fore    the   Eoyal  Society,   March  28, 
Modifications  of  the  Simple  and  Com-      1878. 
pound  Eyes    of   Insects,"    read  be- 


jy SECTS  AND  FLOWERS.  71 

human  sight  at  almost  incredible  distances  for  the  stay- 
at-home  European. 

But  the  composite  plants  offer  by  far  the  most  instruc- 
tive example  of  the  effect  produced  after  many  genera- 
tions of  unconscious  selection  by  the  visits  of  insects. 
The  first  approach  toward  their  mode  of  aggregation 
may  be  seen  in  the  head  of  clover,  where  a  number  of 
separate  little  pea-blossoms  are  collected  into  a  compact 
assemblage  by  the  shortening  of  their  several  stalks.  In 
the  scabious  we  find  the  like  tendency  carried  still 
further  by  the  addition  of  a  broad  receptacle  and  a  bunch 
of  surrounding  leaves,  known  as  an  involucre,  which 
fulfils  the  protective  functions  of  a  calyx  for  the  com- 
pound group.  The  real  calyx,  however,  on  each  single 
blossom,  still  retains  its  original  form,  and  doubtless 
assists  in  the  performance  of  its  proper  office.  But  in  the 
true  composites,  like  daisies  or  dandelions,  the  separate 
flowers  have  almost  mersjed  their  distinct  individualities 
in  that  of  the  complex  whole.  The  calyx  has  become 
degraded  into  a  mere  bundle  of  hairs  (known  as  a  pajjpns), 
which  serves  as  a  float  for  the  mature  seed,  and  forms  the 
"  clock,"  blown  away  by  village  children  from  the  withered 
dandelion  head,  as  well  as  the  gossamer-like  wings  that 
carry  the  thistle  seeds  among  the  farmer's  corn.  The  in- 
volucre here  usurps  the  whole  protective  function  :  and 
the  head  of  flowers  is  mistaken  by  the  ordinary  human 
observer  for  a  single  blossom.  But  if  we  look  close  into 
the  daisy,  we  see  that  its  centre  comprises  a  whole  mass 
of  little  yellow  bells,  each  of  which  consists  of  corolla, 
stamens,  and  pistil.  The  insect  who  alights  on  the  head 
can  take  his  fill  in  a  leisurely  way  without  moving  from 
his  standing-place ;  and  meanwhile  he  is  proving  himself 
a  good  ally  to  the  plant  by  fertilising  one  after  another  of 
its  numerous  ovaries.  Each  tiny  bell  by  itself  would  prove 
too  inconspicuous  to  attract  much  attention  from  the 
passing  bee ;  but  union  is  strength  for  the  daisy  as  for 
the    state,  and   the   little  composites  have   found   their 


72  THE  COLOUR-SENSE. 

co-operative  system  answer  so  well,  that  late  as  was 
their  appearance  upon  the  earth,  they  are  generally 
considered  at  the  present  day  to  be  the  most  numerous 
family  both  in  species  and  individuals  of  all  flowering 
plants. 

Nor  has  the  process  of  differentiation  stopped  even  here. 
Amongst  the  composites  themselves  great  variety  may  be 
observed  in  the  means  adopted  for  the  attraction  of  insects. 
The  simplest  form  of  composite  head,  wdiich  we  see  in  the 
thistle  and  the  artichoke,  consists  of  uniform  flowers,  none 
differing  in  shape  or  colour  from  their  neighbours.  The 
common  English  centaury  shows  an  intermediate  stage,  in 
which  the  outer  florets  are  longer  and  larger  than  those 
in  the  centre  of  the  head.  The  sunflower  and  the  ragwort 
advance  a  step  farther  in  the  same  direction,  their  outer 
florets  having  become  ray-shaped  or  ligulate,  but  still 
preserving  the  yellow  hue  of  the  central  mass.  The  ray 
florets,  in  these  cases,  practically  fulfil  the  functions  of 
petals,  while  the  inner  blossoms  continue  to  act  as  true 
floral  organs.  Finally,  in  the  daisy  and  in  many  chry- 
santhemums, the  outer  florets,  besides  being  prolonged 
into  petal-like  rays,  are  coloured  white,  pink,  mauve,  or 
blue,  while  the  central  mass  retains  its  original  colouration. 
Here  we  find  the  external  row  of  flowers  quite  diverted 
from  its  true  purpose,  and  devoted  almost  exclusively  to 
the  attractive  function. 

Even  now  we  have  not  yet  arrived  at  the  last  stages  of 
the  differentiating  process.  The  complex  heads  of  flowers 
thus  formed  again  unite  into  still  more  complex  masses. 
The  daisy  and  the  sunflower  bear  only  one  composite  head 
on  each  stalk,  but  the  common  thistle  produces  a  whole 
mass  of  heads  in  a  kind  of  umbel,  and  the  ragwort  has 
bunches  of  such  umbels  growing  together  side  by  side. 
In  the  groundsel,  each  head  of  flowers  looks  like  a  single 
blossom ;  in  milfoil,  the  umbellate  form  is  almost  exactly 
reproduced  in  still  wilder  profusion;  while  the  pretty 
waving  golden-rod  caps  the  climax  by  collecting  compound 


INSECTS  AND  FLOWERS.  73 

"bandies  of  heads  into  a  many-branched  and  multitudinous 
plume.  Flowers  too  small  to  succeed  individually  thus 
succeed  in  serried  masses ;  and  masses,  again,  too  small 
for  success  in  single  complexity,  achieve  attention  in  their 
turn  by  reuniting  into  yet  more  complex  groups. 

As  to  the  special  colouring  matter  employed  in  each 
case,  but  little  can  be  said  as  yet  about  its  determining 
causes.  In  a  few  cases,  indeed,  we  can  conclude  with 
some  probability  that  the  existing  hue  has  been  developed 
because  it  subserved,  as  such,  some  special  function. 
Thus  night-flowering  plants  are  usually  pure  white  or 
pale  yellow,  the  very  colours  best  adapted  for  scattering 
the  scanty  moonbeams  or  the  dying  twilight,  and  so 
attracting  the  eyes  of  moths  and  other  crepuscular  insects. 
Again,  Rafflesia,  Hydnora,  Stapdia,  and  many  other  fetid 
flowers,  which  obtain  fertilisation  by  deceiving  flies 
through  their  resemblance  to  putrid  meat,  imitate  the 
lurid  appearance  as  well  as  the  noisome  smell  of  carrion. 
Many  orchids  are  believed  to  be  coloured  in  mimicry  of 
insects,  either  for  the  sake  of  attraction  or  of  protection 
from  hurtful  creatures.  Other  flowers  appear  to  cater 
specially  for  the  peculiar  tastes  of  certain  insects,  which 
exhibit  a  preference  for  red,  blue,  yellow,  or  orange,  as 
the  case  may  be,  and  these  will  receive  more  extended 
treatment  in  the  succeeding  chapter.  Sir  John  Lubbock 
thinks  that  the  lines  or  spots  on  many  flowers  act  as 
guides  for  the  bees,  pointing  out  the  exact  spot  where 
the  honey  may  be  found ;  and  Fritz  Miiller  suggests  that 
their  changing  hues  serve  as  timepieces  to  show  the  right 
moment  for  effecting  fertilisation.!  But  in  the  majority 
of  cases  we  cannot  point  to  any  such  special  determining 
cause  for  the  particular  hue  which  we  find  in  nature.  It 
is  known  that  the  colouring  matters  of  flowers  may  be 
divided  into  two  classes,  the  xanthic  and  the  cyanic,  whose 
types  are  respectively  yellow  and  blue ;  and  these  two 
classes  do  not  readily  pass  into  one  another.     Thus,  we 

^  "  Nature,"  November  29,  1S77. 


74  THE  COLOUR-SENSE. 

cannot  liavG  a  blue  rose  or  a  blue  dahlia,  tliougli  we  may 
vary  the  hues  of  either  blossom  by  proper  treatment 
almost  indefinitely  within  the  prescribed  limit.  Hence, 
it  might  appear  that  each  flower  produced  as  a  rule  those 
colours  which  most  readily  result  from  the  chemical 
properties  of  its  constituents,  varying  the  tint,  so  far  as 
possible,  under  the  influence  of  insect  selection,  in  accord- 
ance with  the  nature  of  the  percipient  eye,  of  the  sur- 
rounding foliage,  and  of  other  adventitious  circumstances 
in  the  environment.  It  might  well  happen,  however,  in 
the  majority  of  cases,  that  any  bright  colour  would  equally 
answer  the  attractive  purpose,  supposing  only  it  contrasted 
sufficiently  with  the  green  leaves  or  other  objects  in  the 
natural  background.  Such,  at  least,  we  know  to  be  the 
fact  with  the  eye  of  man,  who  is  struck  indifferently  by 
the  golden  orange,  the  ruddy  strawberry,  the  rosy-cheeked 
mango,  or  the  purple  grape. 

With  regard  to  the  infinite  variety  of  tints  which  we 
find  in  various  flowers,  it  is  sufficient  to  remember  that 
very  slight  alterations  in  the  physical  conditions  or  in 
the  particular  stock  suffice  artificially  to  produce  such 
varieties  among  cultivated  plants.  Any  one  who  looks 
at  the  multitudinous  shades  of  garden  hyacinths,  dahlias, 
fuchsias,  chrysanthemums,  tulips,  and  pansies,  need  not 
wonder  at  the  great  profusion  of  colour  in  wild  plants. 
Almost  any  shade  seems  easily  procurable  from  another, 
provided  only  it  does  not  overstep  the  natural  limitation 
set  down  above.  In  all  probability,  the  ordinary  colouring 
matters  of  flowers  differ  from  one  another  only  in  the 
minutest  particulars  of  chemical  composition. 

So  far  we  have  been  engaged  in  answering,  to  the  best 
of  our  knowledge,  the  first  question  proposed  above :  Did 
flowers  show  an  original  tendency  to  the  production  of 
coloured  adjuncts  even  prior  to  the  selective  action  of 
insects  ?  We  have  settled  to  our  own  satisfaction — I  hope 
also  to  the  satisfaction  of  the  critical  reader — that  such  an 
original  and  adventitious  tendency  did  really  exist ;  and 


INSECTS  AND  FLOWERS.  75 

we  have  traced  it  up  through  its  various  stages,  as  it 
became,  from  generation  to  generation,  more  and  more 
purposive,  until  at  last  we  have  seen  it  culminate  in  the 
gorgeous  peonies,  tulips,  lilies,  and  rhododendrons  of  our 
modern  flower-s^ardens.  But  all  this  time  we  have  been 
putting  off  the  consideration  of  our  second  question :  Did 
insects  possess  any  tendency  vaguely  to  discriminate  the 
various  colours  apart  from  the  reactive  influence  of  ento- 
mophilous  Howers  ?  To  this  further  inquiry  we  must  now 
address  ourselves  for  a  few  short  minutes. 

The  answer  must  be  a  somewhat  dubious  one — in  a 
certain  sense  negative,  in  another  sense  affirmative.  There 
is  no  reason  to  think  that  insects  could  be  definitely 
affected  by  various  colours  before  the  rise  of  bright-hued 
flowers  had  developed  their  colour-sense.  But  we  must 
remember  that  while  colours  differ  qualitatively  for  us, 
they  also  differ  quantitatively  in  an  absolute  manner. 
Now,  "  to  be  affected  more  or  less,"  as  Professor  Bain  well 
puts  it,  "  is  a  consequence  of  being  affected  at  all ; "  and 
therefore  every  animal  which  has  any  organ  for  the  per- 
ception of  light  must  be  capable  of  quantitatively  differ- 
ential stimulation  by  its  greater  or  less  intensity.  Herein 
we  have  a  slight  original  groundwork  through  which  white 
might  be  distinguished  by  the  primitive  eye  from  green, 
brown,  or  black.  But  the  growth  of  a  distinctive  mode  of 
consciousness,  or,  to  put  it  objectively,  of  distinct  nerve- 
oroans  for  the  various  waves  of  sether,  must  needs  have 
been  the  result  of  long  ages,  during  which  those  insects 
who  best  discriminated  colour  lived  down  on  the  average 
their  less  gifted  compeers.  How  this  result  was  brought 
about  we  cannot  even  guess,  for  here  we  rind  ourselves  on 
the  threshold  of  an  ultimate  metaphysical  problem,  un- 
fathomable as  yet — perhaps  unfathomable  for  ever  !  Why 
the  sensations  of  the  auditory  central  organs  should  differ 
from  those  of  the  optical  central  organs ;  ivliy  the  stimula- 
tion of  a  certain  fibre  and  its  connected  ganglia  should 
yield  the  feeling  of  blue,  while  the   stimulation  of  its 


76  THE  COLOUR-SENSE. 

neigiibour  yields  that  of  red — these  final  questions  we 
cannot  even  pretend  to  guess.  How  the  differentiation 
began,  how  it  continued,  how  it  acts  to-day,  we  do  not 
know,  and  very  probably  we  may  never  know.  But  we 
do  know  this,  that  in  a  developed  sensorium  a  differential 
sensation  is  attached  to  the  differential  stimulation  of  each 
among  several  very  like  nervous  bodies ;  and  that  if  it  were 
not  so,  consciousness  itself  would  be  impossible. 

Passing  over  this  ultimate  problem,  however,  it  is  not 
difficult  to  see  how  a  substance  so  unstable  and  so 
modifiable  as  nerve-matter  might  easily  present  various 
modifications  which  answered  to  the  various  varieties  of 
sether-wave  falling  upon  it.  If  once  such  differentiated 
nerve-terminals  began  to  exist,  all  experience  and  analogy 
show  us  that  they  would  be  followed  by  the  differentiation 
of  their  connected  nerve-centres,  to  each  of  which,  in  this 
mysterious  way,  a  differentiated  mode  of  consciousness 
would  come  to  be  attached.  And  this  is  what  we  mean 
by  colour-sense. 

Vague  and  symbolical  as  such  a  sketch  confessedly 
must  be,  it  would  be  foolish  and  premature  to  fill  in  any 
further  conjectural  details  in  the  present  state  of  our 
knowledge.  We  must  accept  it  as  a  bare  skeleton  of  the 
possible  truth  which  fuller  acquaintance  with  the  nature 
of  nerve-substance  may  some  day  flesh  out  for  us  in  all  its 
minor  aspects.  But  we  are  not  wholly  without  analogies 
which  allow  us  faintly  to  foreshadow  in  our  minds  some 
indefinite  hypothesis  of  its  evolution.  We  know  that  a 
single  material,  such  as  glass,  may  be  so  moulded  into  globes 
that  each  globe  will  not  only  yield,  when  struck,  a  single 
constant  note,  but  will  also  answer  sympathetically  to  that 
note  alone  when  sounded  on  another  instrument.  Now  if 
we  suppose  that  the  nerve-terminals  of  the  insect  eye  were 
similarly  tuned  at  first,  but  so  badly  as  to  vibrate  sympa- 
thetically with  the  whole  gamut  of  separate  sether-waves, 
we  shall  have  a  symbolical  picture  of  an  eye  without  a 
colour-sense.     But  if  we  further  suppose  that,  under  the 


INSECTS  AND  FLOWERS.  77 

influence  of  sundry  incident  causes  unknown,  certain 
amonc^  these  nerve-terminals  became  restricted  in  the 
range  of  their  sympatliies,  so  as  onlv  to  vibrate  in  unison 
with  ?ether-waves  having  a  limited  range  of  frequency, 
then  we  shall  have  a  symbolical  picture  of  an  eye  with  a 
rudimentary  colour-sense.  And  if  natural  selection,  pick- 
ing out,  as  we  know  it  would,  from  the  whole  number  of 
variations  in  either  direction  those  which  varied  most  on 
the  side  of  a  still  more  limited  range,  at  last  produced 
terminals  which  were  affected  only  by  waves  lying  within 
an  extremely  small  compass,  we  should  then  have  the 
symbolical  picture  of  an  eye  with  a  highly  developed 
colour-sense.  Eude  as  this  representation  of  the  possible 
course  of  evolution  must  obviously  be,  it  may  still  answer 
the  purpose  of  enabling  the  reader  diagrammatically  to 
grasp  the  idea  which  would  otherwise  float  vaguely  through 
his  mind  and  elude  every  attempt  to  fix  and  crystallise  it 
into  thouoht.  More  than  this  humble  service  our  rough 
and  materialistic  metaphor  cannot  pretend  to  perform. 

And  now,  to  recapitulate  the  chief  points  of  this  lengthy 
chapter,  let  us  look  back  in  imagination  over  the  whole 
complex  process  here  so  imperfectly  sketched  out,  and 
state  our  hypothetical  conclusions,  for  clearness'  sake,  in 
the  lancTuai^e  of  established  fact.  Amid  the  earliest  forests 
of  our  earth,  green  cryptogamic  vegetation  formed  the 
whole  flora.  But  as  time  went  on,  the  advantages  of 
cross-fertilisation  produced,  through  some  unknown  com- 
bination of  circumstances,  the  earliest  flowering  plants. 
These,  strengthened  by  the  constant  infusion  of  fresh 
blood  (to  use  the  familiar  phrase),  lived  down  the  con- 
sanguineous offspring  of  the  great  ferns  and  horse-tails 
amongst  which  they  grew.  But  such  primeval  flowering 
species  were  all  fertilised  by  the  aid  of  the  wind,  and 
possessed  no  bright  corollas  or  other  coloured  adjuncts. 
The  aspect  of  a  palceozoic  forest  presented  an  almost  un- 
broken sheet  of  monotonous  verdure.  Even  then,  how- 
ever, a  tendency  towards  the  production  of  red  or  yellow 


78  THE  COLOUR-SENSE, 

juices  and  other  colouring  matters  might  have  been  noticed 
in  certain  portions  of  the  different  plants.  The  tendency 
was  especially  displayed  in  those  parts  of  the  organism 
where  energies  were  being  used  up  in  the  performance  of 
physiological  functions ;  this  effect  being  due,  perhaps,  to 
the  process  of  oxidation.  Such  phenomena  might  be 
noticed  both  in  the  dying  leaves  and  in  the  youngest 
shoots  ;  but  they  were  also  to  be  found  in  the  floral  organs 
and  their  neighbourhood.  As  yet,  however,  no  eye  could 
distinguish  them  as  colours :  they  had  only  an  objective 
existence  as  sether-waves  of  unusual  simplicity  and  purity. 
But  among  these  flowers  a  few  undeveloped  and  unspe- 
cialised  insects  sought  their  food.  Some  of  the  blossoms 
thus  obtained  fertilisation  more  easily  than  before;  and 
those  among  them  which  offered  special  attractions  to  the 
insects  were  able  to  effect  a  great  economy  of  pollen, 
besides  being  impregnated  with  immensely  greater  cer- 
tainty than  their  anemophilous  competitors.  Thus  certain 
plants  became  permanently  and  regularly  entomophilous. 
Thenceforward  those  entomophilous  plants  which  pro- 
duced the  greatest  quantities  of  insect  food,  as  honey  or 
pollen,  were  most  often  visited,  and  so  most  regularly 
fertilised.  Again,  out  of  this  number,  whatever  indivi- 
duals most  conspicuously  displayed  the  original  tendency 
toward  bright  and  distinctive  colouration  were  most 
likely  to  strike  the  eyes  of  insects.  Conversely,  whatever 
insects  most  readily  discriminated  the  nascent  patches  of 
colour  were  best  able  (other  things  equal)  to  secure  their 
food.  So  the  production  of  coloured  floral  whorls,  and  the 
perfectioning  of  the  insect  colour-sense,  went  on  pro- 
gressing side  by  side.  The  various  flowers  entered  into 
unconscious  competition  with  one  another  for  the  visits 
of  their  fertilisers  ;  and  those  which  could  specially  lay 
themselves  out  for  the  attention  of  a  single  species  there'by 
procured  impregnation  with  greater  ease  and  certainty. 
Thus  arose  the  quaintly-shaped  bells,  labiates,  snap- 
dragons, orchids,  and  other  irregular  flowers,  whose  forms 


INSECTS  AND  FLOWERS.  79 

are  definitely  correlated  to  those  of  their  insect  allies. 
Similarly,  an  insect  with  a  specially  long  proboscis,  and 
with  certain  hairy  appendages  on  his  legs  or  forehead, 
might  at  once  abstract  honey  from  flowers  which  no  other 
insect  could  reach,  and  fertilise  deeply-seated  organs 
which  no  other  insect  would  affect.  Thus  arose  the 
specialised  flower-feeders  like  bees  and  butterflies.  Again, 
other  flowers  which  separately  failed  to  attract  the  proper 
insects  might  prove  very  alluring  when  massed  in  large 
bunches.  The  result  is  seen  in  the  development  of  com- 
pound blooms  like  clover,  lilac,  horse-chestnut,  and  the 
various  composites,  which  last  undergo  still  further  selec- 
tions, ultimately  producing  yet  more  compound  forms. 
At  length  the  colour-sense  of  insects,  thus  aroused, 
strengthened,  and  fully  developed,  is  employed  for  other 
purposes,  of  defence,  protection,  the  chase  after  prey,  the 
search  for  mates,  or  similar  life-serving  actions ;  and  these 
activities  once  more  react  on  the  growing  sense,  so  as  to 
increase  its  definiteness  and  its  worth.  Last  of  all,  the 
colour-sense  is  employed  by  the  insects  themselves,  as  we 
shall  see  in  a  future  chapter,  as  an  sesthetic  instrument 
in  the  choice  of  mates,  and  so  indirectly  produces,  throuo-h 
sexual  selection,  the  brilliant  hues  of  butterflies,  beetles, 
and  all  the  other  exquisite  winged  or  creeping  articulates 
which  fill  the  gorgeous  cabinets  of  our  museums. 

In  this  list  of  what  the  colour-sense  owes  to  the  hues 
of  blossoms,  we  might  further  include  many  facts  with 
regard  to  humming-birds,  sunbirds,  and  other  flower- 
feeding  vertebrates.  But  these  belong  properly  to  a  later 
stage  in  our  inquiry ;  and  enough  has  already  been  said 
or  hinted,  I  believe,  to  show  how  fundamental  a  fact  in 
the  history  of  the  colour-sense  and  its  reactions  is  the 
primitive  tendency  towards  the  display  of  bright  hues 
around  the  floral  reproductive  organs.  Already  we  have 
here,  indeed,  the  origin  of  many  among  those  brilliant 
objects  which  we  noted  as  wanting  in  the  Carboniferous 
world — the  world  without  a  colour-sense.     We  must  here- 


8o  THE  COLOUR-SENSE. 

after  go  on  to  inquire  what  was  the  development  of  the 
remainder ;  and  w^e  shall  find,  when  we  search  the  records 
of  evolution,  that  no  small  proportion  of  these,  too,  may 
be  ultimately  traced  back,  through  some  remote  and  in- 
direct pedigree,  to  the  lovely  and  varied  tints  of  tropical 
or  woodland  flowers. 


(    8i     ) 


CHAPTER  V. 

THE  COLOUR-SENSE  IN  INSECTS. 

Throughout  the  \yliole  of  the  preceding  chapter  we  have 
taken  for  granted  the  existence  of  a  developed  colour- 
sense  in  some  at  least  amongst  the  insects  of  modern 
times.  We  have  tried  to  show  what  were  the  circum- 
stances which  gave  it  origin,  and  what  the  steps  by  which 
it  reached  its  present  supposed  perfection.  But  now  a 
deeper  question  arises,  a  question  due  to  a  destructive 
criticism  which  might  seek  to  overthrow  our  whole  super- 
structure by  denying  that  modern  insects  do,  as  a  matter 
of  fact,  possess  any  colour-sense  whatsoever.  In  the  face 
of  such  a  possible  criticism  we  must  review  all  the  various 
proofs  of  colour-perception  in  articulate  animals  which 
experiment  or  observation  may  reveal  to  our  patient 
search. 

This  course  is  rendered  the  more  necessary  because 
within  the  last  few  years  the  existence  of  a  faculty  for 
the  discrimination  of  different  hues,  even  in  primitive 
man  himself,  has  been  gravely  called  in  question,  both 
in  this  country  and  in  Germany,  by  competent  authorities 
in  various  walks  of  science  or  criticism.  Mr.  Gladstone 
first  suggested  that  the  Homeric  poems  contained  no 
evidence  of  a  colour-sense  amongst  the  Akhaians  of  that 
early  date.i  Many  years  later.  Dr.  Lazar  Geiger  noticed 
that  the  colour-words  employed  in  the  Bible,  the  Vedas, 
the  Zend-Avesta,  and  other  early  works,  were  very  vague 

1  Gladstone,  "Studies  on  Homer,"  vol.  iii.  §  4. 


82  THE  COLOUR-SENSE. 

and  indeterminate.  1  Dr.  Magnus,  a  distinguislied  German 
oculist,  next  followed  up  the  hint  thus  thrown  out,  and 
endeavoured  to  prove,  in  two  learned  pamphlets,-  that  the 
colour-perception  of  civilised  man  was  a  faculty  of  quite 
recent  development,  and  that  so  lately  as  some  3000  years 
ago  mankind  was  utterly  incapable  of  distinguishing 
between  violet,  green,  blue,  and  yellow.  These  views 
were  further  popularised  by  Mr.  Gladstone  in  a  later 
paper,^  and  have  been  partially  adopted  by  several 
scientific  authorities,  including  even  that  staunch  evolu- 
tionist, Mr.  A.  E.  Wallace,  the  joint-discoverer  of  natural 
selection.^  Indeed,  although  the  allegations  of  Dr. 
Magnus  and  his  friends  have  not  gone  entirely  un- 
answered,^ yet  it  would  seem  as  though  the  scientific 
world  generally,  in  Germany  at  least,  was  prepared  to 
accept  them  as  representing  the  approximate  truth. 

To  the  evolutionist,  however,  this  crude  and  ill-digested 
theory  can  hardly  seriously  reconmiend  itself.*^  The  sup- 
position that  any  mode  of  perception  so  distinct  and  so 
varied  as  our  colour-sense  could  be  developed  in  the 
short  space  of  time  intervening  between  the  Homeric 
Akhaians  and  our  own  epoch  seems  little  short  of  in- 
credible. The  few  centuries  which  have  rolled  past 
during  that  interval  form  but  a  single  pulse  of  the  pen- 
dulum whose  seconds  make  up  the  epochs  of  geological 
evolution.     To  me,  it  appears  rather  that  the  colour-sense 

^  Zur  Entwickelungsgeschichte  der  264, 423;  by  an  anonymous  critic  in  the 

Menschheit,  chap,  iii.,  passim,  Stutt-  Allgemeine  Zeitung,  IMarch  8,  1878; 

gart,  1871.  by  Prof.    Blackie,    read    before   the 

2  Die  Geschichtliche  Entwickelung  Royal  Society  of  Edinburgh,  January 

des  Farbensinnes,  Leipzig,  1877,  and  1878;  by  Prof.   Robertson  Smith  in 

in  Preyer's  Physiologischer  Abhand-  "Nature,"   December    6,    1877;    by 

lungen,  I.  ix.  515,  Dr.  Pole  in    "Nature,"   October  24 

2  "The  Colour-Sense"  in  "Nine-  and   31,    1878;    and    by   myself    in 

teenth  Century,"  October  1877.  "Mind,"  January  1878. 

■*  "Colour  in  Animals  and  Plants,"  ^  I  learn  by  a  private  letter  from 

"  Macmillan's    Magazine,"     October  Mr.  Wallace  that,  on  fuller  considera- 

1877.  tion,  he  cannot  endorse  Dr.  Magnus's 

5  Readers  desirous  of  following  up  views    so    implicitly   as    he   was   at 

the  whole  discussion  will  find  papers  first  inclined  to  do,  and  he  has  since 

on  this  question  by  Mr.  Darwin  and  partially   retracted    his   adhesion  in 

Dr.  Krause  in  "Kosmos,"  1877,  pp.  "  Tropical  Nature,"  p.  246. 


THE  COLOUR-SENSE  IN  INSECTS,  Z^ 

of  man  is  derived,  through  his  mammalian  ancestry,  from 
a  long  line  of  anterior  generations,  and  that  its  origin 
must  be  sought  for  in  ages  before  a  solitary  quadrumanous 
animal  had  appeared  upon  the  face  of  the  earth.    Holding 
this  view,  it  becomes  incumbent  on  me   to   propose    a 
counter-theory  to  that  of  Dr.  Magnus  and  Mr.  Gladstone  ; 
a  theory  which  will  trace   back   our  colour-sense  to  its 
ultimate   sources  in  the  bright  hues  of  vegetal  products 
like  fruits  and  flowers.     And  it  becomes  necessary  also  to 
seek   for   every  possible    fact  which  goes  to  prove  the 
existence   of    a    similar   faculty   throughout   the   whole 
animal  world.     For  if  even  man  himself,  "  the  head  and 
crown  of  things,"  did  not  possess  any  such  power  until  a 
few  hundred  years  since,  how  can  we  suppose  that  the 
lower  animals,  including  the  humble  little  insects,  have 
been  for  ages  in  enjoyment  of  this  highest  sensuous  gift  ? 
It  may  be  asked,  however,  "  Why  take  the  trouble  to 
search  for  recondite  proofs  on  such  a  plain  and  straight- 
forward subject  ?     Why  not  try  at  once  a  few  simple  and 
direct  experiments  upon  the  colour-perception  of  various 
insects,  beasts,  and  birds  ?  "     The  suggestion  is  a  natural 
one,  and  yet  it  is  not  so  easy  to  act  upon  as  would  at  first 
appear  to  be  the  case.      Experiments   of   the    sort  are 
difficult  to  devise,  and  still  more  difficult  to  carry  out 
successfully  to  any  definite  result.     We  cannot  ask  the 
animals  to  detail  their  sensations,  and  we  find  it  hard  to 
invent  decisive  or  crucial  tests  of  an  objective  character. 
A  few  lucky  exceptions  will  be  described  in  the  following 
pages,  but  they  are  mere  oases  amongst  a  desert  of  lament- 
able  failures.      As   a  rule,   animals  refuse  in  the  most 
provoking  manner  to  take  any  notice  of  the  psychological 
traps  which  you   have  carefully  baited  as  tests  of  their 
sensations.     For  the  most  part,  we  must  rely  upon  the 
less  satisfactory  method  of  observation,  and  upon  various 
indirect  conclusions,  each  of  which  has  separately  very 
little  weight.    In  short,  the  evidence  in  favour  of  a  colour- 
sense  amongst  the  lower  animals  is  purely  cumulative.  Each 


84  THE  COLOUR-SENSE. 

link  in  the  argument  is  but  a  slender  support ;  yet  I  hope 
to  show  as  we  proceed  that  the  whole  strand,  formed  of 
variously  twisted  chains,  is  collectively  strong  enough  and 
sure  enough  to  support  the  burden  of  a  weighty  conclusion. 
Happily,  as  regards  the  higher  insects,  we  can  start  fair 
with  a  set  of  decisive  experiments  tried  by  Sir  John 
Lubbock.  That  patient  and  minute  observer  saw  grounds 
for  believing  that  bees  were  attracted  by  the  hues  of 
flowers.  However,  to  make  assurance  doubly  sure,  he 
placed  slips  of  glass  smeared  with  honey  on  paper  of 
various  colours,  black,  white,  yellow,  orange,  blue,  and 
red.  The  general  results  may  be  given  in  the  original 
words.  "  A  bee  which  was  placed  on  the  orange  returned 
twenty  times  to  that  slip  of  glass,  only  once  or  twice 
visiting  the  others,  though  I  moved  the  position  and  also 
the  honey.  The  next  morning  again  two  or  three  bees 
paid  twenty-one  visits  to  the  orange  and  yellow,  and  only 
four  to  all  the  other  slips  of  glass.  I  then  moved  the 
glass,  after  which,  out  of  thirty-two  visits,  twenty-two 
were  to  the  orange  and  yellow."  ^  However,  this  prefer- 
ence did  not  depend  upon  an  inability  to  discern  the  blue, 
for  on  another  occasion,  says  the  author,  "  I  had  ranged 
my  colours  in  a  line,  with  the  blue  at  one  end.  It  was 
a  cold  morning,  and  only  one  bee  came.  She  had 
been  several  times  the  preceding  day,  generally  to  the 
honey  which  was  on  the  blue  paper.  This  day  also  she 
came  to  the  blue.  I  moved  the  blue  gradually  along  the 
line  one  stage  every  half  hour,  during  which  time  she 
paid  fifteen  visits  to  the  honey,  in  every  case  going  to 
that  which  was  on  the  blue  paper."  Sir  John  Lubbock, 
however,  never  relies  upon  single  or  few  experiments. 
Accordingly,  he  tried  once  more  at  a  later  date  with 
greater  variation  in  the  circumstances.  "  On  the  1 2th  of 
July,"  he  says,  "  I  brought  a  bee  to  some  honey  which  I 
placed  on  blue  paper,  and  about  three  feet  off  I  placed  a 

^  Journal  of  the  Linnean  Society,  ing  me  copies  of  all  his  papers 
vol.  xii.  p.  129.  I  have  to  thank  Sir  and  lectures  on  this  interesting 
John  Lubbock  for   kindly  forward-    question. 


THE  COLOUR-SENSE  IN  INSECTS,  85 

similar  quantity  of  lioney  on  orange  paper.  After  she 
had  returned  twice,  I  transposed  the  papers ;  but  she 
returned  to  the  honey  on  the  blue  paper.  After  she  had 
made  three  more  visits,  always  to  the  blue  paper,  I  trans- 
posed them  again,  and  she  again  followed  the  colour, 
though  the  honey  was  left  in  the  same  place."  A  series 
of  careful  observations  followed,  which  are  detailed  in  a 
tabular  form  ;  but  my  readers  will  probably  be  satisfied 
with  a  general  summary,  to  the  effect  that  thirty  conse- 
cutive visits  were  all  made  to  the  same  colour,  in  spite  of 
four  separate  transpositions.  On  one  of  these  occasions, 
says  Sir  John,  "At  8.5  she  returned  to  the  old  place, 
and  was  just  going  to  alight ;  but  observing  the  change  of 
colour,  without  a  moment's  hesitation  darted  off  to  the 
blue.  No  one  who  saw  her  at  that  moment  could  have 
entertained  any  further  doubt  about  her  perceiving  the 
difference  between  the  two  colours."  ^ 

Similar  results  were  obtained  with  wasps.  At  6  A.M. 
on  September  13,  1875,  Sir  John  observes,  ''I put  a  wasp 
to  some  honey  on  green  paper  and  about  a  foot  off  I  put 
some  more  honey  on  orange  paper.  The  wasp  kept  re- 
turning to  the  honey  at  the  usual  intervals.  At  8.30  I  trans- 
posed the  papers  ;  but  the  wasp  followed  the  colour.  At 
9  o'clock  I  transposed  the  papers  again,  but  not  the  honey  ; 
she  returned  again  to  the  green,  from  which  it  would  ap- 
pear that  she  was  following  the  colour,  not  the  honey. 
At  10.20  I  again  transposed  them,  with  the  same  result."  2 

It  should  be  mentioned,  however,  that  later  experi- 
ments led  Sir  John  Lubbock  to  the  conclusion  that  bees  do 
not  so  easily  discriminate  between  blue  and  green  as  be- 
tween other  colours — a  very  natural  fact,  considering  how 
slight  is  the  objective  difference  between  these  shades.  It 
would  also  appear  that  though  wasps  can  distinguish 
colours,  they  are  less  guided  by  them  than  is  the  case 
with  bees.^     This  we  might  have  expected  a  priori  from 

^  Journal  of  the  Linnean  Society,  ^  See  part  iv.  of  Sir  John  Lubbock's 
vol.  xii.  p.  232.  investigations  in  Journ.    Linn.  Soc, 

-  Ibid.,  p.  237.  vol.  xii.  p.  312  seq. 


86  THE  COLOUR-SENSE. 

the  diversity  of  habits  of  the  two  insects,  and  we  shall  see 
hereafter  that  the  difference  has  important  bearings  on 
the  question  of  relative  tastes. 

With  respect  to  ants,  Sir  John  Lubbock's  experiments, 
though  read  before  the  Linnean  Society,  have  not  at  the 
date  of  writing  yet  been  published  in  its  Transactions.  It 
must  suffice,  therefore,  without  anticipating  the  author's 
statement,  to  notice  here,  that  though  these  insects  are 
very  defective  in  the  sense  of  vision,  depending  much  more 
largely  upon  touch  and  smell,  they  are  evidently  affected 
in  a  distinctive  manner  by  the  red  and  violet  ends  of  the 
spectrum.  Of  course  the  habits  of  ants  would  not  lead  us 
to  credit  them  with  the  necessary  circumstances  for  giving 
rise  to  a  developed  colour-sense ;  nor  are  their  reactions 
on  external  nature  of  the  same  startling  character  as  those 
which  we  observe  in  the  case  of  the  fully-winged  insects, 
like  bees  and  butterflies.  Nevertheless,  it  is  interesting 
to  observe  that  even  here  a  groundwork  of  faint  discri- 
mination evidently  exists,  which  might  possibly  have  been 
developed  into  a  perfect  sense  had  the  circumstances  of 
ant-life  so  determined  its  evolution. 

Observation  in  many  ways  confirms  the  results  thus 
obtained  by  experiment.  Let  us  look  first  at  the  evidence 
on  this  head  which  can  be  derived  from  the  visits  of  bees 
and  butterflies  to  flowers. 

We  have  seen  already  that  one  main  difference  between 
anemophilous  and  entomophilous  flowers  consists  in  the 
fact  that  while  the  former  are  usually  small,  greenish,  and 
inconspicuous,  the  latter  are  usually  large,  brilliant,  and 
deeply  coloured  with  white,  red,  blue,  or  yellow.  We 
have  the  high  authority  of  Mr.  Darwin  for  the  statement, 
as  an  invariable  rule,  "  That  when  a  flower  is  fertilised  by 
the  wind  it  never  has  a  gaily-coloured  corolla."  ^  And 
though  the  converse  proposition  is  not  strictly  true  in 
every  case,  yet  a  large  proportion  of  those  blossoms  which 

^  Origin  of  Species,  p.  127. 


THE  COLOUR-SENSE  IN  INSECTS.  87 

depend  for  fertilisation  upon  insects  are  noticeable  for 
their  bright  and  flaunting  hues. 

Xow,  the  structures  in  which  the  brilliant  pigments 
reside  have  absolutely  no  function  except  that  of  attract- 
ing the  insect  agents  for  fertilisation.  But  these  struc- 
tures, as  we  have  already  seen,  are  produced  by  the  plant 
at  an  enormous  physiological  cost,  often  so  as  to  engage 
by  far  the  greater  portion  of  all  its  energies.  Unless  we 
allow,  then,  that  roses,  tulips,  lilies,  and  rhododendrons 
have  developed  their  large  and  showy  corollas  for  the  sake 
of  allurinsj  their  insect  allies,  we  shall  be  reduced  to  believe 
that  they  have  produced  these  expensive  and  useless  ad- 
juncts for  no  other  purpose  than  that  of  wasting  their 
substance  in  riotous  living.  Such  a  supposition  involves 
a  simple  physical  absurdity.  If  any  plant  could,  by  any 
accidental  combination  of  circumstances,  once  acquire  so 
bad  a  habit,  it  must  necessarily  stand  at  a  disadvantage  in 
comparison  with  all  other  plants,  and  so  be  quickly  extin- 
guished in  the  ceaseless  struggle  and  competition  of  ter- 
restrial life.  We  cannot  for  a  moment  believe  that  any 
structure  could  exist  at  all,  far  less  spread  itself  through 
all  the  most  successful  species  of  a  dominant  class,  unless 
it  subserved  some  function  of  great  utility  to  the  organism 
in  which  it  is  found. 

Nor  are  we  left  here  entirely  to  such  a  'priori  reasoning. 
It  happens  that  a  few  aberrant  plants  possess  two  forms  of 
flowers — the  one  entomophilous,  and  often  appearing  in  the 
spring ;  the  other  self-fertilised,  and  often  appearing  in  the 
autumn.  Of  this  phenomenon  the  common  violet  offers  a 
well-known  example.  The  entomophilous  blossoms,  which 
seem  to  be  frequently  sterile,  and  to  answer  the  purpose 
of  such  occasional  cross-fertilisation  as  may  keep  up  the 
vigour  of  the  stock,  are  distinguished  by  the  usual  coloured 
corolla,  as  well  as  by  a  sweet  and  attractive  perfume  in 
certain  species.  But  the  self-fertilised  or  clcistogamous 
blossoms,  which  in  many  ways  recall  the  spore-cases  of 
cryptogams,  are  quite  green  and  inconspicuous,  so  much 


88  THE  COLOUR-SENSE. 

so,  that  no  ordinary  observer  would  call  tliem  flowers  at 
all,  but  would  set  them  down  as  fruits  or  seed-vessels. 
These  latter  blossoms  do  most  of  the  effective  reproductive 
work ;  but  as  they  do  not  aim  at  cross-fertilisation,  and  so 
do  not  require  the  aid  of  insects,  they  have  entirely  lost 
all  semblance  of  coloured  floral  whorls,  and  consist  merely 
of  hidden  fructifying  elements.  Thus  nature  herself,  as  it 
were,  makes  an  experiment  for  us  which  clearly  demon- 
strates, by  the  Method  of  Difference,  the  real  function  of 
the  pigmented  corolla. 

Like  results  are  shown  in  the  case  of  many  plants  be- 
longing to  mainly  entomophilous  families.  True  anemo- 
philous  flowers,  whose  ancestors  have  been  anemophilous 
for  all  past  generations,  and  have  never  learnt  to  depend 
upon  insects  at  all,  possess  only  the  two  effective  sexual 
whorls,  with  at  most  some  appendage  having  more  or  less 
the  nature  of  a  calyx.  But  certain  plants,  which  appar- 
ently belong  by  descent  to  mainly  entomophilous  tribes, 
seem  to  have  dropped  the  habit  of  insect-fertilisation,  and 
to  have  reverted  once  more  to  wind-fertilisation.  In  all 
(or  almost  all)  these  cases,  where  the  corolla  still  exists  at 
all  in  a  rudimentary  form,  bearing  witness  to  their  ances- 
tral habit,  the  petals  have  grown  quite  small  and  dwarfed 
(because  their  original  function  is  gone),  and  have  once 
more  resumed  the  green  appearance  of  ordinary  leaves. 
In  short,  we  see  that  where  flowers  require  the  aid  of 
insects  they  almost  always  bid  for  it  by  assuming  bright 
hues ;  but  that  those  flowers,  anemophilous  or  cleistoga- 
mous,  which  do  not  need  their  aid,  are  normally  destitute 
of  such  hues,  while  those  plants  which  once  required  their 
aid,  but  have  ceased  to  do  so,  rapidly  lose  their  coloured 
adjuncts,  in  accordance  with  that  Law  of  Parsimony  where- 
by all  structures  whose  functions  are  no  longer  necessary 
become  finally  obsolescent.  How  these  facts  can  be  ac- 
counted for  if  we  suppose  insects  to  be  destitute  of  a 
colour-sense  it  would  baffle  the  cleverest  theorist  to  say. 

In  some  few  instances  we  even  possess  actual  proof  that 


THE  COLOUR-SENSE  IN  INSECTS.  89 

insects  are  attracted  by  the  bright  hues  of  petals.  Thus 
Mr.  Anderson  noticed  that  when  the  corolla  of  certain 
blossoms,  so  constructed  as  to  favour  or  almost  ensure 
cross-fertilisation,  had  been  cut  away,  the  insects  never 
discovered  or  visited  the  flowers.^  "  I  proved  the  import- 
ance of  the  gaily  coloured  corolla,"  says  Mr.  Darwin,  "  by 
cutting  off  the  large  lower  petals  of  several  flowers  of 
Lobelia  erinus,  and  these  flowers  were  neglected  by  the 
hive-bees,  which  were  incessantly  visiting  the  other 
flowers."  ^ 

Descending  to  particular  instances,  we  find  that  while 
most  bright-coloured  blossoms  ofi'er  the  visiting  insect 
some  real  advantage  in  the  shape  of  honey,  other  unprin- 
cipled plants,  trading  upon  the  general  faith  in  a  connec- 
tion between  colour  and  food,  delude  insects  into  visiting 
them  by  their  hue  alone.^  Again,  certain  insects,  as  Mliller 
has  observed,  visit  certain  flowers  only ;  and  in  other 
cases,  a  particular  insect,  during  a  single  day,  confines 
himself,  for  some  reason  of  his  own,  to  some  one  chosen 
species.  Numerous  naturalists  have  put  on  record  the 
preferences  which  individual  insects  have  shown  on  special 
occasions  for  one  kind  of  blossom  alone.  A  single  case 
must  suffice  for  all.  That  careful  observer,  Mr.  H.  O. 
Forbes,  saw  "  by  the  roadside,  near  Kew  Bridge  Station, 
several  species  of  Hymenoptera,  of  the  genus  Bomlus 
principally;  one  visited  thirty  flowers  of  Lamium  pur- 
jpureum  in  succession,  passing  over  without  notice  all  the 
other  plants  on  the  same  bank — species  of  Convolvulus, 
Ruhus,  Solarium.  Two  other  species  of  JBomhus  and  a 
Pieris  rapce  also  patronised  the  Lamium,  seeking  it  out 
deep  in  the  thicket,  thrusting  their  probosces  even  into 
withered  cups,  although  the  Ruhus  flowers  were  far  more 
accessible,  and  seemed  much  more  attractive,  beins^  fresh 
and   well-expanded."  ^     The  pages  of  scientific  journals 

1  Darwin,  "Cross  and  Self-Fertili-  ^  Lubbock,  "  British  Wildflowers," 
sation  of  Plants,"  p.  87,  p.  11. 

^  Ibid.,  p.  176.  ^  "Nature,"'  Xovember  22,  1877. 


90  THE  COLOUR-SENSE. 

during  the  last  few  years  have  positively  teemed  with 
similar  instances  from  all  parts  of  the  world. 

Furthermore,  the  varying  colours  of  flowers  seem 
adapted,  as  we  saw  in  the  last  chapter,  to  attract  parti- 
cular insects  at  particular  periods  of  inflorescence.  I 
have  already  mentioned  the  case  of  a  Lantana  described 
by  F.  MuUer  as  altering  in  hue  at  different  times  during 
its  maturation,  being  yellow  on  the  first,  orange  on  the 
second,  and  purple  on  the  third  day.  "  This  plant,"  says 
Mliller,  "  is  visited  by  various  butterflies.  As  far  as  I  have 
seen,  the  purple  flowers  are  never  touched.  Some  species 
inserted  their  proboscis  both  into  yellow  and  into  orange 
flowers  (JDanais  erippus,  Pieris  aripa) ;  others,  as  far  as  I 
have  hitherto  observed,  exclusively  into  the  yellow  flowers 
of  the  first  day  {Heliconius  apseiides,  Coloenis  julia,  Eurema 
leucc).  ...  If  the  flowers  fell  off  at  the  end  of  the  first 
day,  the  inflorescence  would  be  much  less  conspicuous  : 
if  they  did  not  change  their  colour,  much  time  would  be 
lost  by  the  butterflies  inserting  their  proboscis  in  already 
fertilised  flowers."^  In  another  species  of  the  same  genus 
the  flowers  are  lilac,  but  the  entrance  of  the  tube  is 
marked  with  yellow,  surrounded  by  a  white  circle.  These 
yellow  and  white  markings,  which  probably  serve  as  guides 
for  the  insect  allies,  disappear  entirely  on  the  second  day. 

And  now,  from  the  evidence  supplied  by  flowers,  we 
may  pass  on  to  the  evidence  supplied  by  the  colours  of 
insects  themselves.  I  do  not  here  propose  to  enter  upon 
the  consideration  of  those  hues  which  depend  for  their 
origin  upon  sexual  selection ;  that  part  of  our  cumulative 
argument  must  be  delayed  to  a  later  chapter.  But  we 
may  fittingly  consider  at  the  present  point  the  proofs  of  a 
colour-sense  in  insects  afforded  by  the  curious  phenomenon 
of  mimicry,  so  fully  illustrated  by  Mr.  Wallace  and  Mr. 
Bates. 

It  is  now  an  established  fact  that  certain  animals  have 

1  "Nature,"  Xov ember  29,  1877. 


THE  COLOUR-SENSE  IN  INSECTS.  91 

survived  in  the  struggle  for  existence  by  means  of  some 
special  resemblance  to  other  species  or  to  objects  in  the 
environment  which  gives  them  a  special  chance  of  deceiv- 
ing prey,  escaping  the  notice  of  enemies,  or  adopting  some 
similar  protective  device.  Colour  enters  largely  into  the 
special  adaptations  thus  produced,  and  many  insects 
have  been  largely  modified  in  their  colouration  by  the 
action  of  such  mimetic  selection.  But,  as  a  rule,  the 
particular  hues  or  lines  have  reference  less  to  the  eyes  of 
insects  themselves  than  to  the  eyes  of  the  reptiles,  birds, 
or  mammals  which  prey  upon  them ;  and  these  cases  will 
therefore  be  more  fully  considered  when  we  come  to  treat 
of  the  colour-sense  in  vertebrates.  In  a  few  instances, 
however,  protective  imitation  seems  to  have  been  pro- 
duced in  certain  insects  with  reference  to  the  eyes  of  other 
species  in  their  own  class ;  and  these  latter  cases  may 
properly  be  treated  under  the  present  heading. 

First  of  all,  we  may  take  the  instance  of  those  flies 
which  live  in  a  sort  of  social  parasitism  among  the  hives 
or  nests  of  bees.  These  flies  have  acquired  belts  of  colour 
and  other  imitative  appendages  closely  resembling  those 
of  the  host  upon  whose  stores  they  commit  their  depreda- 
tions, while  their  larvse  actually  live  by  devouring  the 
larvae  of  the  bees  themselves.  Obviously,  any  fly  which 
entered  a  beehive  could  only  escape  detection  and  ex- 
termination at  the  hands  of  its  inhabitants,  provided  it  so 
far  resembled  them  as  to  be  mistaken  at  a  first  glance  by 
the  community  for  one  of  their  fellows.  Thus  any  fly 
which  showed  the  slightest  superficial  resemblance  to  a 
bee  miohfc  at  first  be  enabled  to  rob  their  storehouses 
with  impunity,  while  such  flies  would  escape  continued 
detection  from  generation  to  generation  just  in  proportion 
as  they  more  and  more  closely  approximated  to  the  ap- 
pearance of  their  unwilling  hosts.  For,  as  Mr.  Belt  has 
well  pointed  out,  while  the  mimicking  species  would 
become  naturally  more  numerous  from  age  to  age,  the 
senses  of  the  mimicked  species  would  become  naturally 


92  THE  COLOUR-SENSE. 

sharpened  by  the  habit  of  detecting  flimsy  pretences  ;  and 
so  at  last  very  close  resemblance  might  be  expected  to 
arise.^  In  the  particular  instance  now  under  notice,  I 
learn  from  Mr.  Lowne,  who  has  carefully  measured  the 
curvature  of  the  facets  in  the  compound  eyes  of  insects 
(upon  which,  of  course,  depends  the  minimal  size  of  ap- 
prehensible objects),  that  the  mimicry  has  proceeded  just 
so  far  as  the  structure  of  the  bee's  eye  would  lead  him  to 
expect,  and  no  further.  In  other  words,  Mr.  Lowne  is 
inclined  to  suppose,  if  measurements  of  angular  distance 
subtended  can  guide  him,  that  such  a  fly  is  indistinguish- 
able by  a  bee  from  one  of  his  own  species  within  the 
limits  of  ordinary  vision.^ 

Mr.  Bates  mentions  a  still  more  interesting  case  of  some 
showy  coloured  Brazilian  spiders  (which,  of  course,  are  not 
themselves  insects  in  the  scientific  sense),  "who  double 
themselves  up  at  the  base  of  leaf-stalks,  so  as  to  resemble 
flower-buds,  and  thus  deceive  the  insects  upon  which 
they  prey."^  Sir  Joseph  Hooker  believes  that  an  Indian 
Mantis,  or  praying-insect,  similarly  deludes  the  little 
creatures  which  form  its  food  by  its  extraordinary  like- 
ness to  a  leaf.'^  Another  rapacious  example  of  the  same 
genus  exactly  mimics  the  white  ants,  whom  it  devours 
quietly  and  unsuspected.^  But  all  these  curious  facts  are 
thrown  into  the  shade  by  a  third  Mantis,  for  which  Sir 
Charles  Dilke  stands  as  voucher — a  bloodthirsty  wretch, 
whose  head  and  fang^s  have  been  moulded  into  the  ima^e 
of  an  orchid,  with  a  deceptive  blossom  which  closes  upon 
the  insect  who  seeks  for  food  in  its  treacherous  arms. 

Sometimes  even  higher  animals  seem  to  have  acquired 

^  The  aSTaturalist  in  Nicaragua,  p.  was  a  Syrian  Laphria,  and  the  crea- 

383.  ture  mimicked  a  wasp. 

-   For  a  very  perfect   instance   of  '^  The  Naturalist  on  the  Amazons, 

such  mimetic  resemblance,  where  the  p.  54. 

colour  is  especially  noticed  in  great  •*   Himalayan   Journal,   vol.    ii.    p. 

detail,  see  an  interesting  paper  b}"  JNIr.  306. 

Neville  Goodman  in  "Proc.   Camb.  ^   Wallace,  "Contributions  to  the 

Phil.  Soc,"  vol.    iii,   part  2,  March  Theory  of  Natural  Selection,"  p.  98. 
1878,  p.  25.   In  this  case  the  mimicker 


THE  COLOUR-SENSE  IN  INSECTS.  93 

similar  disguises  in  order  to  deceive  the  insects  for  which 
they  lie  in  wait.  Thus  Mr.  Belt  notices  a  green  ISTicara- 
guan  lizard,  looking  like  the  herbage  by  which  it  is  sur- 
rounded, and  decked  with  leaf-like  expansions,  which 
serve  to  conceal  its  predacious  nature  from  passing  beetles 
or  flies. 1  How  far  the  greenness  of  lizards  and  forestine 
birds  in  general,  or  the  sandy  hue  of  those  which  frequent 
deserts,  may  serve  them  as  aids  in  escaping  the  notice  of 
prey  upon  which  they  creep,  is  too  uncertain  a  question 
to  be  urged  in  evidence  as  to  the  colour-sense  of  insects, 
and  yet  too  interesting  to  be  passed  by  without  at  least 
an  allusion. 

In  all  these  instances,  various  predatory  species  have 
acquired  mimetic  resemblances  for  the  sake  of  deceiving 
their  quarry ;  but  in  other  cases  the  defenceless  booty 
turns  the  tables  upon  the  tyrants,  and  is  accordingly 
enabled  to  elude  their  hungry  quest.  Thus  Mr.  Wallace 
tells  us  of  a  cricket  w^hich  exactly  reproduces  the  features 
of  its  foe  the  sandwasp ;  ^  while  Mr.  Belt  saw  a  green  leaf- 
like locust,  overrun  by  foraging  ants,  yet  remaining  as 
motionless  as  the  leaves,  whose  colour  and  texture  it  so 
faithfully  mimicked.  This  latter  creature  appeared  to 
have  some  dim  instinctive  knowledge  of  the  fact  that  its 
safety  depended  upon  its  absolute  immobility,  for  even 
when  lifted  by  the  hand  from  the  ground,  it  continued 
strenuously  to  preserve  its  rigid  attitude.^ 

But  indeed,  to  any  mind  unbiassed  by  preconceptions 
derived  from  another  sphere  of  thought,  the  grand  evi- 
dence in  favour  of  an  insect  colour-sense  is  to  be  found, 
not  in  isolated  instances,  but  in  the  broad  expanse  of 
meadow  and  hillside  around  us.  The  million  hues  of 
spring  or  summer  flowers  have  no  meaning  and  no  ex- 
planation on  any  other  hypothesis.  The  colour-sense  of 
bees  and  butterflies  has  metamorphosed  the  world ;  and 

^  Naturalist  in  Nicaragua,  p.  12. 

2  Contributions  to  the  Theory  of  Natural  Selection,  p.  99. 

2  Naturalist  in  Nicaragua,  p.  19. 


94  THE  COLOUR-SENSE. 

we  must  seek  for  its  indications  on  every  plain  and  moun- 
tain of  every  country  in  the  earth. 

A  human  analogy  will  make  clear  the  magnitude  of  the 
changes  in  the  face  of  nature  due  to  the  reactive  effects 
of  the  insect  colour-sense.  Man  has  wrought  many  altera- 
tions in  the  aspect  of  the  fauna  and  flora  of  all  coun- 
tries which  he  has  brought  under  his  sway.  He  has  cut 
down  the  forests,  cleared  the  jungle,  irrigated  the  desert, 
reclaimed  the  stony  waste.  Whatever  plants  or  animals 
served  him  for  food,  clothing,  or  other  useful  purposes, 
he  has  selected,  propagated,  and  carried  with  him  in  his 
wanderings  from  shore  to  shore.  Whatever  others  proved 
useless  or  positively  noxious,  he  has  extirpated  from  their 
native  haunts.  His  fields  glow  with  golden  corn  or  dark- 
green  maize ;  with  millet,  barley,  oats,  or  rice ;  with  vines, 
hops,  or  sugar-cane ;  w^ith  yams,  potatoes,  plantain,  or 
bananas ;  with  flax,  hemp,  cotton,  oil-seeds,  or  fibres.  His 
orchards  are  laden  with  apples,  plums,  peaches,  pears, 
oranges,  olives,  mangoes,  and  papaws.  His  meadows  are 
stocked  with  the  clover,  lucerne,  vetches,  and  grass  which 
feed  his  flocks  and  herds.  The  woodland  itself  is  spared 
only  to  supply  him  with  timber  for  firewood  or  building. 
In  like  manner,  the  wild  beasts  of  the  forest  have  given 
place  to  his  cattle,  his  horses,  and  his  sheep.  Camels, 
elephants,  and  llamas  bear  his  burdens  on  their  patient 
backs.  Alpacas  and  merinos,  the  goats  of  Kashmir  and 
the  yaks  of  Tibet,  supply  his  woven  fabrics.  Even  insects 
are  not  exempt ;  silkworms  fatten  on  his  mulberry  trees, 
and  nopaleries,  specially  planted  for  that  purpose,  afford 
sustenance  to  his  cochineal  flies.  The  wolves,  bears, 
foxes,  tigers,  and  venomous  snakes  retire  before  his  face, 
and  he  wages  a  perpetual  warfare  with  the  intrusive  weeds 
which  seek  to  find  a  root-hold  among  his  growing  crops. 
Such  are  the  changes  which  man  has  impressed  upon  the 
lands  where  he  has  made  his  settled  home. 

But  all  these  alterations  are   mere  surface   scratches 
compared  with  the  immense  revolution  wrought  in  the 


THE  COLOUR-SENSE  IN  INSECTS.  95 

features  of  nature  by  the  unobtrusive  insect.  Half  tlie 
flora  of  the  earth  has  taken  the  imprint  of  his  likes  and 
his  necessities.  While  man  has  only  tilled  a  few  level 
plains,  a  few  great  river  valleys,  a  few  peninsular  moun- 
tain slopes,  leaving  the  vast  mass  of  earth  untouched  by 
his  hand,  the  insect  has  spread  himself  over  every  land  in 
a  thousand  shapes,  and  has  made  the  whole  flowering 
creation  subservient  to  his  daily  wants.  His  buttercup, 
his  dandelion,  and  his  meadow-sweet  grow  thick  in  every 
English  field.  His  mint  clothes  the  hillside ;  his  heather 
purples  the  bleak  grey  moorland.  High  up  among  the 
Alpine  heights  his  gentian  spreads  its  lakes  of  blue; 
amid  the  snows  of  the  Himalayas  his  rhododendrons 
gleam  with  crimson  light.  Even  the  wayside  pond  yields 
him  the  crowfoot  and  the  arrowhead,  while  the  broad 
expanses  of  Brazilian  streams  are  beautified  by  his  gor- 
geous waterlilies.  The  insect  has  thus  turned  the  whole 
surface  of  the  earth  into  a  boundless  flower-garden,  which 
supplies  him  from  year  to  year  with  pollen  or  honey,  and 
itself  in  turn  gains  perpetuation  by  the  baits  that  it  offers 
for  his  allurement. 

If  any  man  can  seriously  doubt  that  these  changes  are 
really  due  to  a  colour-sense  in  the  little  creatures  which 
live  upon  the  beautiful  flowers,  if  he  can  imagine  that  the 
plant  has  produced  its  gorgeous  petals  for  no  other  pur- 
pose than  that  of  suicidal  wastefulness ;  that  the  Mantis 
has  grown  into  the  perfect  semblance  of  a  leaf  from  pure 
wanton  causeless  mimicry  ;  that  the  lurid  red  of  fly-ferti- 
lised blossoms  bears  its  likeness  to  the  mangled  flesh  of 
animals  by  a  simple  freak  of  creative  power;  then  the 
whole  science  and  philosophy  of  the  last  hundred  years 
have  been  thrown  away  upon  him,  and  he  may  return  at 
leisure  to  the  blind  and  hopeless  chance  of  the  eighteenth- 
century  atheists.  Even  if  we  could  allow  the  strangely 
gratuitous  hypothesis  of  a  distinguished  naturalist,^  that 

1  Mr.  A.  R.  "Wallace,  "  On  the  Colours  of  Plants  and  Animals,"  "  Mac- 
millan's  Magazine,"  September  1877,  ad  init. 


96  THE  COLOUR-SENSE. 

tlie  colours  of  organic  beings  were  originally  developed 
by  natural  causes,  with  a  sort  of  divine  aftertliought  re- 
garding the  pleasure  which  man  might  derive  from  their 
contemplation,  yet  we  cannot  blind  ourselves  to  the  abso- 
lute necessity  of  their  performing  from  the  very  first  some 
special  utilitarian  function.  Not  even  the  watchmaker 
deity  of  Paley  himself,  one  may  suppose,  would  have 
invented  flowers  in  the  Secondary  age  for  the  sole  gratifi- 
cation of  man  in  the  Post-tertiary.  To  put  it  briefly,  if 
insects  have  not  a  colour-sense,  then  the  whole  universe 
must  be  nothing  more  than  a  singularly  happy  concourse 
of  fortuitous  atoms.  The  theist  and  the  evolutionist  are 
equally  ready  to  disclaim  with  all  their  might  this  gro- 
tesque and  monstrous  supposition. 


(     97    ) 


CHAPTER  VI. 

BIRDS   OR   MAMMALS   AND   FRUITS. 

What  insects  are  to  bright-hued  flowers,  birds  and  mam- 
mals are  to  bright-hued  fruits.  And  we  might  almost  say, 
though  with  more  reservation,  what  flowers  are  to  the 
colour-sense  in  insects,  fruits  are  to  the  colour-sense  in 
birds  and  mammals. 

Accordingly,  we  may  fairly  conclude  that  bright-coloured 
fruits  belong  to  a  much  later  geological  age  than  entomo- 
philous  blossoms.^  We  need  not  here  transport  ourselves 
in  imagination  to  the  green  expanse  of  palceozoic  jungles, 
unenlivened  by  scarlet  flowers  or  gaudy  insects ;  we  have 
only  to  place  ourselves  amid  the  comparatively  modern 
flora  of  the  Tertiary  age,  surrounded  by  forest  trees  of 
familiar  aspect,  and  tenanted  by  animals  whose  shape 
differs  but  little  from  those  of  our  own  historical  epoch. 
Already  the  ground  spreads  a  carpet  of  soft  grass  beneath 
our  feet;  already  simple  forms  of  insect-fertilised  blos- 
soms stand  out  in  profusion  as  brilliant  points  of  colour 
among  the  green  foliage  around.  It  is  true  we  see  no 
highly-differentiated  daisies  or  thistles,  with  their  clus- 
tered heads  of  tubular  bells ;  no  strangely-shaped  orchids 
or  snapdragons,  with  their  forms  nicely  adjusted  to  those 
of  the  fertilisincr  bees  ;  but  we  find  a  fair  abundance  of 
unspecialised  flowers,  with  a  regular  corolla  of  separate 
pieces,  such  as  we  know  so  well  in  the  buttercup,  the 
poppy,  or  the  geranium.  Moreover,  we  may  see  among 
them,  not  merely  the  little  dingy  creeping  insects  of  the 

See  Wallace's  "  Tropical  Nature,"  p.  228. 

G 


98  THE  COLOUR-SENSE. 

Carboniferons  deltas,  but  flitting  butterflies  with  coloured 
wings,  and  flower-haunting  beetles  of  exquisite  metallic 
slieen.  These  brij^hter  forms  of  insect  life  have  been  de- 
veloped  in  the  vast  cycles  of  that  immeasurable  interim 
by  the  selective  action  of  sexual  preference,  working 
through  a  taste  for  brilliant  hues  which  has  been  origi- 
nally formed  in  the  search  for  food  ;  but  this  portion  of 
our  subject  we  must  remove  from  its  proper  historical 
place,  owing  to  the  exigencies  of  logical  treatment,  and 
relegate  it  to  a- later  chapter,  where  we  may  consider  the 
question  of  sexual  selection  in  its  ensemble,  as  exhibited 
throughout  all  departments  of  the  animal  kingdom.  For 
the  present,  we  must  content  ourselves  by  taking  for 
granted  the  existence  among  the  Tertiary  forests  of  gaily- 
tinted  insects  and  gorgeous  lizards,  as  well  as  that  of 
crimson  leaves  and  orange  blossoms.  Nay,  more,  we  may 
probably  allow  that  the  higher  vertebrate  types  which 
lived  in  those  primitive  modern  wilds  possessed  some 
more  or  less  distinct  form  of  colour-perception,  derived 
perhaps  from  their  earlier  marine  ancestors,  and  kept  alive 
l-y  exercise  upon  these  varied  objects  in  their  actual  envi- 
ronment. Yet,  in  spite  of  such  facts  and  probabilities,  it 
will  be  well  worth  while  briefly  to  trace  the  origin  of 
bright-hued  fruits,  as  we  have  already  traced  the  origin  of 
bright-hued  flowers,  both  because  the  colour-sense  of  the 
highest  vertebrates  probably  owes  much  to  the  reaction  of 
these  brilliant  food-stuffs,  and  because  the  taste  for  colour 
in  man  himself  may  be  plausibly  referred  to  the  arboreal 
habits  of  his  ante-human  progenitors,  Furthermore,  we 
shall  see  reason  to  conclude  hereafter  that  the  plumage  of 
the  most  beautiful  birds  and  the  fur  or  skin  of  the  most 
highly-coloured  mammals  are  due  to  the  love  for  bright 
hues  originally  developed  in  connection  with  the  pulpy 
fruits ;  and  this  conclusion  affords  another  reason  why  we 
should  first  inquire  into  the  history  of  their  evolution. 

The  ultimate  object  of  flowering  is  the  production  of 
seeds,  that  is  to  say,  of  embryo  plants^  destined  to  replace 


■      BIRDS  OR  MAMMALS  AND  FRUITS.  99 

their  parents,  and  continue  the  life  of  the  species  to  future 
generations.  The  vessel  which  includes  one  or  more  such 
seeds,  the  produce  of  a  single  flower,  is  known  in  botanical 
parlance  as  a  fruit.  But  as  it  often  happens  that  the  ripe 
pistils  of  more  than  one  blossom  become  united  together 
into  a  single  mass,  instances  of  which  habit  may  be  seen 
in  the  fig  and  the  mulberry,  it  becomes  convenient  to 
describe  these  aggregate  seed-vessels  also  as  compound 
fruits.  In  the  language  of  ordinary  life,  however,  a  fruit 
means  something  very  different  from  such  hard  and  dry 
seed-vessels  as  those  of  poppies,  beans,  or  thistles.  We 
understand  by  the  word,  in  daily  usage,  some  sweet,  soft, 
pulpy  object,  more  or  less  connected  with  the  seeds,  and 
usually  possessing  some  bright-coloured  portion.  To  these 
latter  structures  we  shall  generally  give  the  designation  of 
fruits-proper,  to  distinguish  them  from  such  among  their 
like  as  are  merely  fruits  by  botanical  courtesy.  Fruits- 
proper,  then,  in  this  restricted  sense,  form  the  special  object 
of  our  present  investigation. 

The  botanical  fruit  consists  of  a  covering  or  pericarp, 
often  extremely  thin  and  almost  papery,  enclosing  one  or 
more  ripe  seeds.  But  other  connected  portions  of  the  plant, 
for  example,  the  swollen  flower-stalk  and  the  receptacle, 
frequently  coalesce  so  thoroughly  with  these  essential 
organs  that  it  becomes  impossible  to  distinguish  them, 
even  for  technical  purposes.  This  is  especially  the  case 
with  fruits-proper,  where  the  edible  portion  quite  as  often 
consists  of  some  irregular  adjunct  as  of  the  juicy  pericarp 
itself.  Accordingly,  in  the  following  account,  I  shall  take 
the  liberty  of  dealing  a  little  broadly  with  the  technical 
terms  of  botany,  suppressing  all  unnecessary  detail,  and 
only  dwelling  upon  the  simplest  and  most  salient  points. 

The  ideal  form  of  fruit  would  consist  of  a  plain  peri- 
carp enclosing  a  single  seed ;  and  though  such  fruits  are 
comparatively  rare,  one  may  reasonably  suppose  that  the 
earliest  flowering  plants  would  in  all  probability  produce 
seed-vessels  of  a  very  simple  kind,  in  which  the  separate 


loo  THE  COLOUR-SENSE. 

seeds  were  small  and  inconspicuous,  thougli  relatively 
numerous.  Indeed,  the  gymnosperms,  or  pine  and  cycad 
group,  which  appeared  upon  the  earth  before  any  other 
phanerogamous  plants,  cannot  be  said  to  possess  any  fruit 
at  all  in  the  proper  sense  of  the  term.  Moreover,  there  is 
reason  to  believe  that  early  plants  produced  large  quan- 
tities of  seeds  which  were  relatively  ill  provided  with 
coverings  or  nutriment,  and  which  depended  rather  upon 
their  number  than  upon  any  special  adaptation  for  their 
chance  of  survival.  But  as  time  went  on,  slight  adventi- 
tious  variations  in  the  nature  of  the  seeds  or  their  cover- 
ings might  prove  useful  in  protecting  them  from  some 
one  or  other  amonsf  the  numerous  dans^ers  to  which  their 
fellows  were  exposed,  and  so  might  give  them  an  extra 
advantage  in  the  struggle  for  existence.  The  most  notice- 
able among  these  variations  is,  that  which  consists  in 
the  extra  supply  of  energetic  material  for  the  sprouting 
plantlet. 

A  young  plant  consists  of  an  embryo  whose  growth 
depends  upon  the  liberation  of  energy  contained  in  its 
hydro-carbonaceous  or  albuminoid  materials,  by  union 
with  the  free  oxygen  of  the  air.  The  energetic  substances 
upon  which  it  feeds  were  laid  up  for  it  by  the  parent 
plant,  either  in  the  growing  seed-leaves  (cotyledons),  as 
in  the  case  of  the  pea  and  bean,  or  in  a  separate  albu- 
minous mass,  as  in  the  case  of  the  wheat  tribe.  But  such 
energetic  materials  are  exactly  the  portions  of  plants 
which  form  the  best  food-stuffs  for  animals ;  and  accord- 
ingly, as  birds  and  mammals  multiplied  upon  the  face  of 
the  earth,  it  must  happen  that  those  very  seeds  which 
possessed  the  best  chance  of  survival  through  their  stores 
of  nutriment  would  also  be  the  ones  which  lay  most  ex- 
posed to  the  ravages  of  animal  foes.  Hence  plants  are 
compelled  to  adopt  many  devices  whereby  they  may  secure 
themselves  against  such  depredations. 

One  common  plan  is  that  by  which  some  underground 
structure,  such  as  a  bulb,  tuber,  corm,  or  root,  is  made  to 


BIRDS  OR  MAMMALS  AND  FRUITS.  loi 

supplement,  or  in  many  cases  almost  to  supersede,  the 
natural  mode  of  reproduction  by  seeds.  This  is  seen  in 
numerous  plants,  such  as  potatoes,  onions,  beets,  and  many 
grasses.  But  perhaps  the  most  interesting  case  is  that  of 
the  ground-nuts,  whose  "  hypogean  "  fruit  is  buried  deep 
in  the  earth,  so  as  to  escape  the  notice  of  all  but  burrow- 
ing animals.  Yet  even  these  species,  which  try  to  conceal 
their  stores  of  food  by  hiding  them  under  the  soil,  fall  a 
prey  at  last  to  the  snouts  of  rodents  or  swine.  In  fact,  it 
must  naturally  happen  that,  as  young  plants  and  animals 
feed  on  exactly  the  same  energetic  substances,  every 
device  on  the  part  of  the  plant  will  soon  be  met  by  a 
counter-device  on  the  part  of  the  hungry  animal.^ 

Each  species  of  plant  must,  of  course,  solve  for  itself 
the  problem,  during  the  course  of  its  development,  whether 
its  energies  will  be  best  employed  by  hoarding  nutriment 
for  its  own  future  use  in  bulbs  and  tubers,  or  by  produc- 
ing richly-endowed  seeds  which  will  give  its  offspring  a 
better  chance  of  rooting  themselves  comfortably,  and  so 
surviving  in  safety  amid  the  ceaseless  competition  of  rival 
species.  The  various  cereals,  such  as  wheat,  barley,  rye, 
and  oats,  have  found  it  most  convenient  to  grow  afresh 
with  each  season,  and  to  supply  their  embryos  with  an 
abundant  store  of  food  for  their  sustenance  during  the 
infant  stage  of  plant  life.  Their  example  has  been  fol- 
lowed by  peas  and  other  pulses,  by  the  wide  class  of  nuts, 
and  by  the  majority  of  garden  fruits.  On  the  other  hand, 
the  onion  and  the  tiger-lily  store  nutriment  for  themselves 
in  the  underground  stem,  surrounded  by  a  mass  of  over- 
lapping or  closely-wound  leaves,  which  we  call  a  bulb ; 
the  iris  and  the  crocus  lay  by  their  stock  of  food  in  a 
woody  or  fleshy  stalk ;  the  potato  makes  a  rich  deposit 
of  starch  in  its  subterraneous  branches  or  tubers;  the 
turnip,  carrot,  radish,  and  beet  use  their  root  as  the  store- 
house  for   their   hoarded   food-stufl's ;    while   the  orchis 

1  See  an  article  on  "  The  Origin  of    August  1S78,  a  large  part  of  wbicli  I 
Fruits  "  in  the  Cornhill  Magazine  for    have  transferred  to  this  chapter. 


I02  THE  COLOUR-SENSE, 

produces  each  year  a  new  tubercle  by  the  side  of  its 
existing  root,  and  this  second  tubercle  becomes  in  turn 
the  parent  of  its  next  year's  flowering  stem.  Perhaps, 
however,  the  common  colchicum  or  meadow-saffron  affords 
the  most  instructive  instance  of  all;  for  during  the  summer 
it  sends  up  green  leaves  alone,  which  devote  their  entire 
time  to  the  accumulation  of  food-stuffs  in  a  corm  at  their 
side  \  and  when  the  autumn  comes  round,  this  corm  pro- 
duces, not  leaves,  but  a  naked  flower-stalk,  which  pushes 
its  way  through  the  moist  earth,  and  stands  solitary  before 
the  October  winds,  depending  wholly  upon  the  stock  of 
nutriment  laid  up  for  it  in  the  corm. 

Now,  if  we  look  at  the  materials  used  as  food  by  man 
or  other  frugivorous  creatures,  we  shall  see  that  they  con- 
sist almost  universally  of  these  reservoirs  of  energetic 
material,  laid  up  by  the  plant  for  itself  or  its  descendants. 
It  is  true  that  the  graminivorous  animals,  like  deer,  sheep, 
cows,  and  horses,  live  mainly  off  the  green  leaves  of  grasses 
and  creeping  plants.  But  we  know  how  small  an  amount 
of  food  they  manage  to  extract  from  these  fibrous  masses, 
and  how  constantly  their  whole  existence  is  devoted  to 
the  monotonous  and  imperative  task  of  grazing  for  very 
life.  Those  animals,  however,  who  have  learnt  to  live  at 
the  least  cost  to  themselves  always  choose  the  portions  of 
a  plant  which  it  has  stored  with  nourishment  for  itself  or 
its  offspring.  Men  and  monkeys  feed  naturally  off  fruits, 
seeds,  and  bulbs.  Wheat,  maize,  rye,  barley,  oats,  rice, 
millet,  pease,  vetches,  and  other  grains  or  pulses,  form  the 
staple  sustenance  of  half  mankind.  Other  fruits  largely 
employed  for  food  are  plantains,  bananas,  bread-fruit, 
dates,  cocoa-nuts,  chestnuts,  mangoes,  mangostines,  and 
papaws.  Among  roots,  tubers,  and  bulbs  stored  with 
edible  materials  may  be  mentioned  beet,  carrot,  radishes, 
turnips,  swedes,  ginger,  potatoes,  yam,  cassava,  onions,  and 
Jerusalem  artichokes.  But  if  we  look  at  the  other  vege- 
tables used  as  food,  we  shall  observe  at  once  that  they  are 
few  in  number  and  unimportant  in  economical  value.     In 


BIRDS  OR  MAMMALS  AND  FRUITS.  103 

cabbage,  Brussels  sprouts,  lettuce,  succory,  spinach,  and 
watercress,  we  eat  the  green  leaves;  yet  nobody  would 
ever  dream  of  making  a  meal  off  any  of  these  poor  food- 
stuffs. The  stalk  or  young  sprout  forms  the  culinary  por- 
tion of  asparagus,  celery,  seakale,  rhubarb,  and  angelica, 
none  of  which  vegetables  are  remarkable  for  their  nutri- 
tious properties.  In  all  the  remaining  food-plants  some 
part  of  the  flowering  apparatus  supplies  the  table,  as  in 
tme  artichokes,  where  we  eat  the  receptacle,  richly  stocked 
with  nutriment  for  the  opening  florets ;  or  in  cauliflower, 
wliere  we  choose  the  aborted  flower-buds  themselves.  In 
short,  we  find  that  men  and  the  higher  animals  generally 
support  themselves  upon  those  parts  of  plants  in  which 
energy  has  been  accumulated  either  for  the  future  growth 
and  unfolding  of  the  plant  itself,  or  for  the  sustenance  of 
its  tender  offspring. 

Doubtless  the  earliest  seeds  differed  but  little  from  the 
spores  of  cryptogams  in  the  amount  of  nourishment  with 
which  they  were  provided,  and  the  mode  in  which  they 
were  dropped  upon  the  nursing  soil  beneath.  But  during 
the  great  secondary  and  tertiary  ages  of  geology,  through- 
out whose  loncj  course  first  the  conifers  and  then  the  true 
flowering  plants  slowly  superseded  the  gigantic  horse-tails 
and  tree-ferns  of  the  coal-measures,  many  new  devices  for 
the  dispersion  and  nutrition  of  seeds  were  gradually 
developed  by  the  pressure  of  natural  selection.^  Those 
plants  which  merely  cast  their  naked  embryos  adrift  upon 
the  world  to  shift  for  themselves  in  the  fierce  struggle  of 
stout  and  hardy  competitors  must  necessarily  waste  their 
energies  in  the  production  of  an  immense  number  of  seeds. 
In  fact,  calculations  have  been  made  which  show  that  a 
single  scarlet  corn-poppy  produces  in  one  year  no  less  than 
50,000  embryos ;  and  some  other  species  actually  exceed 

1  I   trust  that  in  the  sequel  the  and  fruits.      Some  little  simplifica- 
critical  botanist  will  excuse  me   for  tiou  is  absolutely  necessjiry  for  gen- 
having    neglected  the    strict    termi-  eral  readers  in  this  the  most  involved 
nology    of  carpological  science,   and  department  of  structural  botany, 
made  no  distinction    between  seeds 


I04  THE  COLOUR-SENSE. 

this  enormous  figure.  If,  then,  any  plant  happens,  by  a 
favourable  combination  of  circumstances,  to  modify  the 
shape  of  its  seed  in  such  a  manner  that  it  can  be  more 
readily  conveyed  to  open  or  unoccupied  spots,  it  will  be 
able  in  future  to  economise  its  strength,  and  thus  to  give 
both  itself  and  its  offspring  a  better  chance  in  the  struggle 
for  life.  There  are  many  ways  in  which  natuj-al  selectioa 
has  effected  this  desirable  consummation. 

The  thistle,  the  dandelion,  and  the  cotton-bush  provide 
their  seeds  with  long  tufts  of  light  hair,  thin  and  airy  as 
gossamer,  by  which  they  are  carried  on  the  wings  of  Ihe 
wind  to  bare  spaces,  away  from  the  shadow  of  tlieir 
mother-plant,  where  they  may  root  themselves  successfully 
in  the  vacant  soil.  The  maple,  the  ash,  and  the  pine  sup- 
ply their  embryos  with  flattened  wings,  which  serve  them 
in  like  manner  not  less  effectually.  Both  these  we  may 
classify  as  wind-dispersed  seeds.  A  second  set  of  plants 
have  seed-vessels  which  burst  open  explosively  when  ripe, 
and  scatter  their  contents  to  a  considerable  distance.  The 
balsam  forms  the  commonest  example  in  our  European 
gardens;  but  a  well-known  tropical  tree,  the  sandbox, 
displays  the  same  peculiarity  in  a  form  which  is  almost 
alarming,  as  its  large,  hard,  dry  capsules  fly  apart  with  the 
report  of  a  small  pistol,  and  drive  out  the  disc-shaped  nuts 
within  so  forcibly  as  to  make  a  blow  on  the  cheek  decidedly 
unpleasant.  These  we  may  designate  as  self-dispersed  seeds. 
Yet  a  third  class  may  be  conveniently  described  as  animal- 
dispersed,  divisible  once  more  into  two  sub-classes,  the 
involuntarily  and  the  voluntarily  aided.  Of  the  former 
kind  we  have  examples  in  those  seeds  which,  like  burrs 
and  cleavers,  are  covered  with  little  hooks,  by  whose 
assistance  they  attach  themselves  to  the  fur  or  wool  of 
passers-by.  The  latter  or  voluntarily  aided  sort  are  exem- 
plified in  fruits-proper,  the  subject  of  our  present  inves- 
tigation, such  as  apples,  plums,  peaches,  cherries,  haws, 
and  brambleberries.  Every  one  of  these  plants  is  provided 
with  hard  and  indigestible  seeds,  coated  or  surrounded  by 


BIRDS  OR  MAMMALS  AND  FRUITS.  105 

a  soft,  sweet,  pulpy,  perfumed,  bright-coloured,  and  nutri- 
tious covering  known  as  fruit.  By  all  these  means  the 
plant  allures  birds  or  mammals  to  swallow  and  disperse 
•  its  undigested  seed,  giving  in,  as  it  were,  the  pulpy  cover- 
ing as  a  reward  for  the  services  thus  conferred. 

But  before  we  go  on  to  inquire  into  the  mode  of  their 
development  we  must  glance  briefly  at  a  second  important 
difference  in  the  constitution  of  seeds. 

If  we  plant  a  grain  of  mustard-seed  in  moist  earth,  and 
allow  it  to  germinate,  we  shall  see  that  its  young  leaves 
begin  from  the  very  first  to  grow  green  and  assimilate 
energetic  matter  from  the  air  around  them.  They  are, 
indeed,  compelled  to  do  so,  because  they  have  no  large 
store  of  nutriment  laid  up  in  the  seed-leaves  for  their 
future  use  by  the  mother-plant.  But  if  we  treat  a  pea  in 
the  same  manner,  we  shall  find  that  it  long  continues  to 
derive  nourishment  from  the  abundant  stock  of  food  trea- 
sured up  in  its  big  round  seed-leaves.  ISTow  of  course  any 
plant  which  thus  learns  to  lay  by  in  time  for  the  wants  of 
its  offspring  gives  its  embryo  a  far  better  chance  of  surviv- 
in""  and  leaving^  descendants  in  its  turn  than  one  which 
abandons  its  infant  plants  to  their  own  unaided  resources 
in  a  stern  battle  with  the  unkindly  world.  Exactly  the 
same  difference  exists  between  the  two  cases  as  that  which 
exists  between  the  wealthy  merchant's  son,  launched  on 
life  with  abundant  capital  accumulated  by  his  father,  and 
the  street  Arab,  turned  adrift  as  soon  as  he  can  walk  alone, 
to  shift  or  starve  for  himself  in  the  lanes  and  alleys  of  a 
great  city. 

So  then  as  plants  went  on  varying  and  improving  under 
the  stress  of  over-population,  it  would  naturally  result  that 
many  species  must  hit  independently  upon  this  device  of 
laying  by  granaries  of  nutriment  for  the  use  of  their  de- 
scendants. But  side  by  side  with  the  advancing  develop- 
ment of  vegetable  life,  animal  life  was  also  developing  in 
complexity  and  perfect  adaptation  to  its  circumstances. 
And  herein  lay  a  difficult  dilemma  for  the  plant.     On  the 


io6  THE  COLOUR-SENSE. 

one  hand,  in  order  to  compete  with  its  neighbours,  it  must 
lay  up  stores  of  starch  and  oil  and  albumen  for  the  good 
of  its  embryos ;  while,  on  the  other  hand,  the  more  indus- 
triously it  accumulated  these  expensive  substances,  the 
more  temptingly  did  it  lay  itself  open  to  the  depredations 
of  the  squirrels,  mice,  bats,  monkeys,  and  other  clever 
thieves,  whose  number  was  daily  increasing  in  the  forests 
round  about.  The  plant  becomes,  in  short,  like  a  merchant 
in  a  land  exposed  to  the  inroads  of  powerful  robbers.  If 
he  does  not  keep  up  his  shop  with  its  tempting  display  of 
wares,  he  must  die  for  want  of  custom ;  if  he  shows  them 
too  readily  and  unguardedly,  he  will  lay  himself  open  to 
be  plundered  of  his  whole  stock-in-trade.  In  such  a  case 
the  plant  and  the  merchant  have  recourse  to  the  self-same 
devices.  Sometimes  they  surround  themselves  with  means 
of  defence  against  the  depredators ;  sometimes  they  buy 
themselves  off  by  sacrificing  a  portion  of  their  wealth  to 
secure  the  safety  of  the  remainder.  Those  seeds  which 
adopt  the  former  plan  we  call  nuts,  while  to  those  which 
depend  upon  the  latter  means  of  security  we  give  the  name 
of  fruits. 

A  nut  is  a  hard-coated  seed,  which  deliberately  lays 
itself  out  to  escape  the  notice  and  baffie  the  efforts  of 
monkeys  and  other  frugivorous  animals.  Instead  of  bid- 
ding for  attention  by  its  bright  hues,  like  the  flower  and 
fruit,  the  nut  is  purposely  clad  in  a  quiet  coat  of  uniform 
green,  indistinguishable  from  the  surrounding  leaves  during 
its  earlier  existence,  while  afterwards  it  assumes  a  dull 
brown  colour  as  it  lies  upon  the  dusky  soil  beneath.  Nuts 
are  rich  in  oils  and  other  useful  food-stuffs ;  but  to  eat 
these  is  destructive  to  the  life  of  the  embryo,  and  therefore 
the  nut  commonly  surrounds  itself  with  a  hard  and  stony 
shell,  which  defies  the  stoutest  teeth  to  pierce  its  thickened 
walls.  Outside  this  sohd  coating  it  often  spreads  a  softer 
covering  with  a  nauseous,  bitter  taste,  so  familiar  to  us  all 
in  the  walnut,  which  at  once  warns  off  the  enemy  from 
attacking  the   unsavoury  morsel.     ISTot  content  with  all 


BIRDS  OR  MAMMALS  AND  FRUITS.  107 

these  protective  devices  of  colour,  taste,  and  hardness,  the 
nut  in  many  cases  contains  poisonous  juices,  and  is  thickly 
clad  in  hooked  and  pointed  mail,  which  wounds  the  hands 
or  lips  of  the  would-be  robber.^  In  brief,  a  nut  is  a  seed 
which  has  survived  in  the  struggle  for  life  by  means  of 
multiplied  protections  against  the  attacks  of  enemies.  We 
cannot  have  a  better  instance  of  these  precautions  than  the 
common  cocoa-nut  palm.  Its  seed  hangs  at  a  great  height 
from  the  ground  on  a  tall  and  slender  stem,  unprovided 
with  branches  which  might  aid  the  climber,  and  almost 
inaccessible  to  any  animal  except  the  persevering  monkey. 
Its  shell  is  very  thick  and  hard,  so  extremely  impermeable 
that  a  small  passage  has  to  be  left  by  which  the  germinat- 
ing shoot  may  push  its  way  out  of  the  stronghold  where  it 
is  born.  Outside  this  shell,  again,  lies  a  thick  matting  of 
hairy  fibres,  whose  elasticity  breaks  its  fall  from  the  giddy 
height  at  which  it  hangs.  Yet,  in  spite  of  all  these  cun- 
ning precautions,  even  the  cocoa-nut  is  not  quite  safe  from 
the  depredations  of  monkeys,  or,  stranger  still,  of  tree- 
climbing  crabs.  The  common  Brazil-nuts  of  our  fruiterers' 
shops  are  almost  equally  interesting,  their  queer,  shapeless 
forms  being  closely  packed  together,  as  they  hang  from 
their  native  boughs,  in  a  hard  outer  shell,  not  unlike  that 
of  the  cocoa-nut.  It  must  be  very  annoying  to  the  un- 
suspecting monkey,  who  has  succeeded  after  violent  efforts 
in  breaking  the  external  coat,  to  find  that  he  must  still 
deal  with  a  mass  of  hard,  angular,  and  uncanny  nuts,  which 
sadly  cut  his  tender  gums  and  threaten  the  stability  of  his 
precious  teeth — those  invaluable  tools,  which  serve  him 
well  in  the  place  of  knives,  hammers,  scissors,  and  all  other 
human  implements. 

A  fruit-proper,  on  the  other  hand,  lays  itself  open  in 
every  way  to  attract  the  attention  of  animals,  and  so  to  be 
dispersed  by  their  aid,  often  amid  the  nourishing  refuse 

^  See  Wallace's  "Tropical  Nature,"  sage  is  extracted  was  in  proof  before 

p.  225  seq.    I  may  perhaps  be  allowed  the  appearance  of  Mr.  Wallace's  book, 

to  add  that  the  article  in  the  "Corn-  though  not  published  till  some  months 

hill  Magazine "  from  which  this  pas-  later. 


loS  THE  COLOUR-SENSE. 

of  their  meals.  It  is  true  that,  with  the  fruit,  as  with 
the  nut,  to  digest  the  actual  seed  itself  would  be  fatal 
to  the  life  of  the  young  plant.  But  fruits  get  OA^er  this 
difficulty  by  coating  their  seeds  first  with  a  hard,  indiges- 
tible shell,  and  then  with  a  soft,  sweet,  pulpy,  and  nutri- 
tious outer  layer.  The  purely  accidental  or  functional 
origin  of  this  covering  is  testified  by  the  immense  variety 
of  ways  in  which  it  has  been  developed.  Sometimes  a 
single  seed  has  shown  a  slight  tendency  to  succulence  in 
its  outer  coat,  and  forthwith  it  has  gone  on  laying  up  juices 
from  generation  to  generation,  until  it  has  developed  into 
a  one-seeded  berry.  Sometimes  a  whole  head  of  seeds  has 
been  surrounded  by  a  fleshy  stem,  and  the  attention  of 
animals  has  thenceforward  encouraged  its  new  habit  by 
ensuring  the  dispersion  of  its  embryos.  A  few  of  the 
various  methods  by  which  fruits  attain  tlieir  object  we 
shall  examine  in  detail  further  on :  it  will  suffice  for  the 
present  to  point  out  that  any  property  which  secured  for 
the  seed  dispersion  by  animal  agency  would  at  once  give 
it  an  advantage  over  its  fellows,  and  thus  tend  to  be 
increased  in  all  future  sjenerations. 

So,  then,  as  birds,  squirrels,  bats,  monkeys,  and  the 
higher  animals  generally  increased  on  the  face  of  the 
earth,  every  seed  which  showed  a  tendency  to  surround 
itself  with  succulent  pulp  would  obviously  gain  a  point 
thereby  in  its  rivalry  with  other  species.  Accordingly,  as 
we  might  naturally  expect,  fruits  which  have  been  deve- 
loped to  suit  the  taste  of  birds  and  mammals  are  of  much 
more  recent  geological  origin  than  flowers,  which  have 
been  developed  to  suit  the  taste  of  insects.  For  example, 
there  is  no  family  of  plants  which  contains  a  greater  num- 
ber of  fruity  seeds  than  the  rose  tribe,  in  which  are  com- 
prised the  apple,  pear,  plum,  cherry,  blackberry,  raspberry, 
strawberry,  quince,  medlar,  loquat,  peach,  apricot,  and 
nectarine,  besides  the  humbler  hips,  haws,  sloes,  and  com- 
mon hedge-fruits,  which,  though  despised  by  lordly  man, 
form  the  chief  winter  sustenance  of  such  among  our  Bri- 


BIRDS  OR  MAMMALS  AND  FRUITS.  109 

tisli  birds  as  do  not  migrate  to  warmer  climates  during  our 
chilly  December  days'  IS'ow,  no  trace  of  tlie  rose  tribe 
can  be  discovered  until  Miocene  times ;  in  other  words,  no 
fruit-bearers  appear  before  the  evolution  of  the  fruit-eaters 
who  called  them  into  existence ;  while,  on  the  other  hand, 
the  rapid  development  and  variation  of  the  tribe  in  the 
succeeding  epoch  shows  how  great  an  advantage  it  derived 
from  its  tendency  to  produce  edible  seed-coverings. 

But  not  only  must  these  coverings  be  succulent  and 
nutritious ;  tliey  must  also  be  conspicuous  and  alluring. 
For  the  attainment  of  these  objects  the  fruit  has  recourse 
to  just  the  same  devices  which  had  already  been  so  suc- 
cessfully initiated  by  the  insect-fertilised  flowers.  It 
collects  into  its  pulpy  substance  a  quantity  of  that  com- 
monly-diffused vegetable  principle  which  we  call  sugar. 
Now  sugar,  from  its  crystalline  composition,  is  peculiarly 
adapted  for  acting  upon  the  exposed  nerves  of  taste  in  the 
tongues  of  vertebrates;  and  the  stimulation  which  it  affords, 
like  all  healthy  and  normal  ones,  when  not  excessive  in 
amount,  is  naturally  pleasurable  to  the  excited  sense.  Of 
course,  in  our  own  case,  the  long  habituation  of  our  frugi- 
vorous  ancestors  to  this  particular  stimulant  has  rendered 
us  peculiarly  sensitive  to  its  effects.  But  even  from  the 
first,  there  can  be  little  doubt  that  a  body  so  specially 
fitted  to  arouse  sensation  in  the  gustatory  nerve  must  have 
afforded  pleasure  to  the  unspecialised  palates  of  birds  and 
rodents ;  for  we  know  that  even  in  the  case  of  naturally 
carnivorous  animals,  like  dogs,  a  taste  for  sugar  is  ex- 
tremely noticeable.  So  then  the  sweet  juices  of  the  fruit 
were  early  added  to  its  soft  and  nutritive  pulp  as  an  extra 
attraction  for  the  animal  senses. 

But  the  greatest  need  of  all,  if  the  plant  would  succeed 
in  enticing  the  friendly  parrot  or  the  obsequious  lemur  to 
disperse  its  seed,  is  that  of  conspicuousness.  Let  the  fruit 
be  ever  so  luscious  and  ever  so  laden  with  sweet  syrups,  it 
can  never  secure  the  suffrages  of  the  higher  animals  if  it 
lies  hidden  beneath  a  mas  i  of  green  foliage,  or  clothes  itself 


no  THE  COLOUR-SENSE. 

in  the  quiet  garb  of  the  retiring  nut.  To  attract  from  a 
distance  the  eyes  of  wandering  birds  or  mammals,  it  must 
dress  itself  up  in  a  gorgeous  livery  of  crimson,  scarlet,  and 
orange.  The  contrast  between  nuts  and  fruits  is  exactly 
parallel  to  the  contrast  between  the  wind-fertilised  and 
the  insect-fertilised  flowers.  An  apple-tree  laden  with  its 
red-cheeked  burden,  an  orange  bough  weighed  down  with 
its  golden  spheres,  a  rowan  or  a  holly  bush  displaying 
ostentatiously  its  brilliant  berries  to  the  birds  of  the  air,  is 
a  second  edition  of  the  roses,  the  rhododendrons,  and  the 
maythorns,  which  spread  their  bright  petals  in  the  spring 
before  the  fascinated  eyes  of  bees  and  butterflies.  Some 
gay  and  striking  tint,  which  may  contrast  strongly  with 
the  green  foliage  around,  is  needed  by  the  developing  fruit, 
or  else  its  pulpiness,  its  sweetness,  and  its  fragrance  will 
stand  it  in  poor  stead  beside  its  bright-hued  compeers. 

How  fruits  began  to  acquire  these  brilliant  tints  is  not 
difficult  to  see.  We  found  already,  in  the  case  of  flowers, 
that  all  external  portions  of  a  plant,  except  such  green 
parts  as  are  actually  engaged  in  assimilating  carbon  under 
the  influence  of  solar  energies,  show  a  tendency  to  assume 
tints  other  than  green.  This  tendency  would,  of  course, 
be  checked  by  natural  selection  in  those  seeds  which,  like 
nuts,  are  destroyed  by  animals,  and  so  endeavour  to  escape 
their  notice ;  while  it  would  be  increased  by  natural  selec- 
tion in  those  seeds  which,  like  fruits-proper,  derive  benefit 
from  the  observation  of  animals,  and  so  endeavour  to 
attract  their  attention.  But  it  is  noticeable  that  fruits 
themselves  are  sour,  green,  and  hard  during  their  unripe 
stage,  that  is  to  say,  before  the  seeds  are  ready  to  be 
severed  from  the  mother-plant ;  and  that  they  only  acquire 
their  sweet  taste,  brilliant  colour,  and  soft  pulp  just  at  the 
time  when  their  mature  seeds  become  capable  of  a  separate 
existence. 

The  connection  of  these  changes  with  the  process  of 
oxidation  is  far  more  certain  and  more  marked  in  the  case 
of  fruits  than  in  that  of  flowers.     During  their  early  state, 


BIRDS  OR  MAMMALS  AND  FRUITS.  iii 

pulpy  fruits  have  the  structure  and  chemical  composition 
of  leaves.  But  as  they  mature,  they  gradually  pass  through 
the  acid  stage,  and  finally  reach  that  of  ripening,  when  their 
gum,  their  cellulose,  and  their  acids  are  partially  converted 
into  sugar.  These  alterations  are  accompanied  by  "  a  loss 
of  watery  fluid,  a  slight  increase  of  temperature,  and  an 
evolution  of  carbonic  acid."  "  Saussure  and  Couverchel 
state  that  grapes,  apples,  and  pears,  when  separated  from 
their  respective  plants,  and  kept  at  a  temperature  of  about 
60°  F.,  gave  out  carbonic  acid.  Fremy  found  that  ripe 
fleshy  fruits  gave  out  a  large  quantity  of  carbonic  acid 
when  boiled  in  a  saline  solution.^  Berard  thinks  that 
these  changes  in  fruits  depend  essentially  on  the  action  of 
the  oxygen  of  the  air.  Fleshy  fruits,  he  says,  may  be  pre- 
served with  little  alteration  for  many  weeks  in  vacuo,  in 
nitrogen,  and  in  hydrogen  gas ;  peaches,  plums,  and  apri- 
cots may  be  kept  from  twenty  to  thirty  days,  and  pears 
and  apples  for  three  months,  in  a  sealed  bottle  containing 
a  little  sulphate  of  iron,  lime,  and  water,  which  remove 
the  oxygen  of  the  air.  Fremy  found  that  the  ripening  of 
the  fruit  was  arrested  by  covering  it  with  varnish,  which 
he  supposes  to  act  partly  by  preventing  the  access  of  air, 
and  partly  by  stopping  the  transpiration,  and  thus  check- 
ing the  flow  of  sap  into  the  fruit."  ^ 

It  may  also  be  added  that  here,  as  in  the  case  of  flowers, 
an  original  tendency  towards  colouration  in  seed-coverings, 
quite  apart  from  any  selective  action,  may  be  distinctly 
noted.  Not  only  are  the  spore-cases  of  many  mosses 
prettily  tinted  with  pink  or  yellow,  but  the  fruits  of  many 
flowering  plants  which  have  no  succulent  pulp  yet  ex- 
hibit a  decided  turn  for  coloured  juices.  Instances  may 
be  found  in  the  dock,  and  less  markedly  in  almost  all 
capsuled  fruits.  But  with  fruits,  as  with  flowers,  we  may 
say  roughly  that  all  the  bright-coloured  species  depend 

1  Fremy,  "Recherches  Chimiques        2  Balfour's  Class-Book  of  Botany, 
sur  la   Maturation   des    Fruits, "    in     pp.  604,  606. 
"Comptes  Rendus,"  xix.  784. 


112  THE  COLOUR-SENSE. 

for  tlieir  diffusion  upon  animals,  while  all  tho^e  wliich  do 
not  depend  upon  animals  are  dull.  "  The  smaller  plants," 
says  Mr.  Wallace,  "whose  seeds  simply  drop  upon  the 
ground,  as  in  the  grasses,  sedges,  composites,  umbelliferee, 
&c.,  always  have  dry  and  obscurely-coloured  capsules, 
and  small  brown  seeds.  Others,  whose  seeds  are  ejected 
by  the  bursting  open  of  their  capsules,  as  with  the 
oxalis  and  many  of  the  caryophyllacese,  scrophularia- 
ceae,  &c.,  have  their  seeds  small,  and  rarely  or  never 
edible."  ^ 

In  the  case  of  the  attractively  coloured  fruits,  however, 
Mr.  Wallace  points  out  that  the  actual  seeds  are  of  such 
a  nature  as  to  escape  destruction  when  the  fruit  itself  is 
eaten.  "  They  are  generally  very  small  and  comparatively 
hard,  as  in  the  strawberry,  gooseberry,  and  fig ;  if  a  little 
larger,  as  in  the  grape,  they  are  still  harder  and  less 
eatable ;  in  the  fruit  of  the  rose  (or  hip),  they  are  dis- 
agreeably hairy;  in  the  orange  tribe,  excessively  bitter. 
When  the  seeds  are  larger,  softer,  and  more  edible,  they 
are  protected  by  an  excessively  hard  and  stony  covering, 
as  in  the  plum  and  peach  tribe ;  or  they  are  enclosed  in  a 
tough  horny  core,  as  with  crabs  and  apples.  .  .  .  These 
fruits  may  also  be  sw^allowed  by  some  of  the  larger  fru- 
givorous  birds ;  just  as  nutmegs  are  swallowed  by  pigeons 
for  the  sake  of  the  mace  which  encloses  the  nut,  and 
which,  by  its  brilliant  red  colour,  is  an  attraction  as 
soon  as  the  fruit  has  split  open,  which  it  does  upon  the 
tree."  2 

But  exactly  as  we  saw  that  some  flowers  attract  insects 
by  a  delusive  hope  of  honey  where  no  honey  is  really  to  be 
had,  so  do  some  fruits  hold  out  attractions  of  colour  to 
birds  or  mammals  where  little  or  no  food  is  to  be  had 
in  return.  Thus  many  beans  have  beautiful  coverings, 
wdiich  must  be  purely  deceptive  in  their  nature  for 
though  some  animals  may  perhaps  be  able  to  eat  them, 
yet  these  can  be  of  no  benefit  to  the  plant,  and  it  cannot 

^  Tropical  Nature,  p.  227.  '  Ibid.,  p.  226. 


BIRDS  OR  MAMMALS  AND  FRUITS,  113 

be  for  their  sake,  therefore,  that  the  bright  integument  lias 
been  developed.  An  extreme  case  is  that  of  the  hard 
little  rosary  bean  (Ahrus  jy^^ecatoria),  so  well  known  as 
the  seed  from  which  the  prisoners  in  Cayenne  manufac- 
ture their  pretty  ornaments.  "It  may  be/'  says  Mr. 
Wallace,  "  that  birds,  attracted  by  the  bright  colour  of  the 
seeds,  swallow  them,  and  that  they  pass  through  their 
bodies  undigested,  and  so  get  dispersed."  If  so,  the  in- 
genious naturalist  suggests  that  the  device  may  only 
succeed  with  "  young  and  inexperienced  birds."  I  am 
myself  inclined  to  think,  however,  that  some  plants,  such 
as  our  English  cuckoo-pint  and  the  famous  AYest  Indian 
manchineel,  actually  derive  a  benefit  from  their  poisonous 
properties ;  because  if  eaten  by  birds  or  small  mammals, 
they  might  destroy  their  host,  and  the  seeds  would  thus 
have  an  opportunity  of  germinating  in  the  midst  of  a  rich 
manure-heap,  consisting  of  its  decomposing  body. 

Another  analogy  with  entomophilous  flowers  may  be 
found  in  the  very  variable  nature  of  the  pulpy  and 
coloured  substance.  It  does  not  matter  at  all  what  por- 
tion of  the  seed-covering  or  its  adjacent  parts  happens 
first  to  show  the  tendency  towards  succulence,  sweetness, 
fragrance,  and  brilliancy.  It  serves  the  attractive  purpose 
equally  well  whether  it  be  calyx,  or  stalk,  or  skin,  or  re- 
ceptacle. Just  as  in  the  case  of  flowers,  we  found  that 
the  coloured  portion  might  equally  well  consist  of  stamens, 
petals,  sepals,  bracts,  or  spathe,  so,  but  even  more  conspi- 
cuously in  the  case  of  fruits,  the  attractive  pulp  may  be 
formed  of  any  organ  whatsoever  which  exhibits  the  least 
tendency  towards  a  pulpy  habit,  and  an  accumulation  of 
saccharine  deposits. 

Thus,  in  the  pomegranate,  each  separate  seed  is  enclosed 
in  a  juicy  testa  or  altered  shell ;  in  the  nutmeg  and  the 
spindle-tree,  an  aril,  or  purely  gratuitous  coloured  mass, 
spreads  gradually  over  the  whole  inner  nut ;  in  the  plum 
and  cherry,  a  single  part,  the  pericarp,  divides  itself  into 
two  membranes,  whereof  the  inner  or  protective  coat  is 

H 


114  THE  COLOUR-SENSE. 

hard  and  stony,  while  the  outer  or  attractive  coat  is  soft^ 
sweet,  and  bright  coloured ;  in  the  strawberry,  the  recep- 
tacle, which  should  naturally  be  a  mere  green  bed  for  the 
various  seed-vessels,  grows  high,  round,  pulpy,  sweet,  and 
ruddy ;  in  the  rose,  the  fruit-stem  expands  into  a  scarlet 
berry,  containing  the  seed-vessels  within,  which  also  hap- 
pens in  a  slightly  different  manner  with  the  apple,  pear, 
and  quince ;  while  in  the  fig  a  similar  stem  encloses  the 
innumerable  seeds  belonging  to  a  whole  colony  of  tiny 
blossoms,  which  thus  form  a  compound  fruit,  just  as  the 
daisy  head,  with  its  mass  of  clustered  florets,  forms  a 
composite  flower.  Strangest  of  all,  the  common  South 
American  cashew  tree  produces  its  nut  (which  is  the  true 
fruit)  at  the  end  of  a  swollen,  pulpy,  coloured  stalk,  and 
so  preserves  its  embryo  by  the  vicarious  sacrifice  of  a 
fallacious  substitute.  These  are  only  a  few  out  of  the 
many  ways  in  which  the  selective  power  of  animals  has 
varied  the  surroundings  of  different  seeds  to  serve  a  single 
ultimate  purpose. 

Nor  is  any  plan  too  extravagant  for  adoption  by  some 
aberrant  species.  What  seed-organ  could  seem  less  adapted 
for  the  attraction  of  animals  than  a  cone  like  that  of  pines 
and  fir-trees  ?  Yet  even  this  hard,  scaly  covering  has 
been  modified,  in  the  course  of  ages,  so  as  to  form  a  fruit. 
In  the  cypress,  with  its  soft  young  cones,  we  can  see  dimly 
the  first  step  in  the  process ;  in  the  juniper,  the  cone  has 
become  quite  succulent  and  berry-like ;  and  finally,  in  the 
red  fruit  of  the  yew,  all  resemblance  to  the  original  type 
is  entirely  overlaid  by  its  acquired  traits. 

Equally  significant  is  the  fact  that  closely  allied  species 
often  choose  totally  different  means  for  attracting  or 
escaping  observation.  Thus,  within  the  limits  of  the  rose 
tribe  itself  we  get  such  remarkable  variations  as  the  straw- 
berry, where  the  receptacle  forms  the  fruit ;  the  apple, 
which  depends  on  the  peduncle,  or  swollen  stalk,  for  its 
allurement ;  the  raspberry,  where  each  seed-vessel  of  the 
compound  group  has  a  juicy  coating  of  its  own,  and  so 


BIRDS  OR  MAMMALS  AND  FRUITS.  115 

forth;  while,  on  the  other  hand,  the  potentilla  has  no 
fruit  at  all,  in  the  popular  sense  of  the  word ;  and  the 
almond  actually  diverges  so  far  from  the  ordinary  habits 
of  the  tribe  as  to  adopt  the  protective  tactics  of  a  nut. 
Similarly,  in  the  palm  tribe,  while  most  species  fortify 
themselves  against  monkeys  by  extravagant  hardness,  as 
w^e  see  in  the  vegetable  ivory,  and  the  solid  coquilla  nuts 
from  which  door-handles  are  manufactured,  a  few  kinds, 
like  the  date  and  the  doom-palm,  trust  rather  to  the  soft- 
ness and  sweetness  of  their  pulp  as  aids  to  dispersion. 
The  truth  which  we  learn  from  these  diverse  eases  may 
be  shortly  summed  up  thus  :  Whatever  peculiarities  tend 
to  preserve  the  life  of  a  species,  in  whatever  apposite 
ways,  equally  aid  it  in  the  struggle  for  life,  and  may  be 
indifferently  produced  in  the  most  closely  related  types. 

I  have  given  this  large  amount  of  space  to  the  con- 
sideration of  fruits,  because  I  believe  we  can  hardly  over- 
estimate their  importance  in  quickening  the  colour-sense 
of  the  higher  animals,  and,  above  all,  in  settling  the 
aesthetic  tastes  of  birds,  quadrumana,  and  men.  We  are 
apt  to  forget  how  considerable  an  element  in  the  total 
coloured  environment  of  forestine  animals  is  formed  by 
brilliant  fruits.  The  utilitarian  connection  of  fruits 
generally  has  made  us  cultivate  them  more  for  tlieir 
pulp  and  sweetness  than  for  their  beauty,  and  in  many 
cases  they  have  actually  lost  in  colour  under  cultivation ; 
while  flowers,  being  selected  entirely  for  their  visual 
attractiveness,  have  gone  on  developing  more  and  more 
expanded  masses  of  bright  petals.^  But  if  we  look  at 
a  few  strikinc^  instances,  we  shall  find  that  fruits  almost 
equal  in  native  beauty  their  earlier  rivals,  the  entomophilous 
blossoms.  Among  cultivated  varieties  commonly  grown 
in  Britain,  we  may  take  apples,  plums,  peaches,  cherries, 
grapes,  strawberries,  raspberries,  currants,  and  pumpkins ; 
while  it  may  be  worth  while  to  remind  the  reader  that 

1  See  tins  point  further  elucidated  in  Chapter  XII.,  on  the  ^Esthetic  Value 
of  Colour. 


li6  THE  COLOUR-SENSE. 

certain  otiier  fruits  or  seeds,  which  usually  appear  on  our 
tables  in  a  green  state,  like  cucumbers  and  scarlet-runner 
beans,  have  brilliant  coats  in  their  mature  forms.  Amongst 
English  wild  fruits,  sufficient  examples  will  be  found  in 
the  hips,  haws,  hoUyberries,  mistletoe,  sloe,  mountain  ash, 
barberry,  yew,  juniper,  ivy,  spindle-tree,  arum,  blackberry, 
iris,  saffron,  elder,  and  sea-buckthorn.  The  tropics  and 
sub-tropical  climates,  however,  supply  us  with  far  more 
gorgeous  examples  in  their  oranges,  shaddocks,  lemons, 
mangoes,  star-apples,  pomegranates,  capsicums,  bananas, 
nutmegs,  achees,  egg-fruits,  prickly  pears,  tomatoes,  winter 
cherries,  solanums,  dates,  and  passion-flower  berries.  In 
fact,  we  may  say  that  fruits-proper  exhibit  larger  amounts 
of  brilliant  colouration  than  any  other  class  of  organic 
objects  except  entomophilous  flowers. 


(     117     ) 


CHAPTER  VII. 

THE   COLOUR-SENSE   IN    VERTEBRATES. 

Although  the  perception  of  colour  by  birds  and  mammals 
has  been  taken  for  granted  in  the  preceding  chapter,  and 
although  it  is  practically  all  but  incontestable  that  the 
higher  vertebrates  are  quite  as  fully  endowed  in  this 
respect  as  ourselves,  yet  the  positive  proofs  which  can  be 
advanced  in  favour  of  the  belief  are  very  meagre  and  in- 
sufficient. The  only  real  evidence  is  that  supplied  by  our 
every-day  observation,  but  no  person  familiarly  acquainted 
with  the  habits  of  birds  and  mammals  ever  doubts  for  a 
moment  their  essential  agreement  with  ourselves  so  far  as 
concerns  the  visual  faculties.  Nevertheless,  it  may  be 
well  to  point  out  the  few  positive  facts  which  are  forth- 
coming on  the  subject,  connecting  them  at  the  s^me  time 
with  the  probable  genesis  of  the  developed  sense. 

Apparently  the  perception  of  colour  is  inherited  by  the 
whole  vertebrate  series  from  some  earlier  common  ancestor. 
At  any  rate,  considerable  traces  of  the  colour-sense  may 
be  detected  among  many  marine  invertebrates.  The  best 
known  instance  is  that  of  the  chameleon  shrimp  (Mi/sis 
chaiiiceleo),  which  has  the  power  of  altering  its  own  colour 
in  correspondence  with  the  material  among  which  it  is 
found.  When  lying  on  a  sandy  bottom  it  appears  grey ; 
but  when  lurking  among  seaweed,  it  is  green  or  reddish 
brown,  according  to  the  nature  of  the  background.  This 
change  is  produced  by  means  of  a  reflex  action  connected 
with  the  eye,  for  when  the  animal  is  blinded  it  no  longer 
occurs.     In  other  words,  we  must  suppose  that  when  the 


ii8  THE  COLOUR-SENSE. 

optic  nerve  of  the  shrimp  is  affected  by  the  green  light 
from  a  piece  of  seaweed,  certain  muscles  are  set  in  action, 
voluntarily  or  automatically,  which  cause  a  corresponding 
change  in  the  arrangement  of  the  pigment  cells,  so  that 
the  animal  appears  green  itself.  It  may  be  added,  too, 
that  this  peculiarity  affords  an  indirect  proof  of  a  colour- 
sense  in  the  enemies  of  the  chameleon  shrimp  (which 
cannot  be  more  highly  developed  animals  than  fishes, 
and  may  perhaps  by  other  crustaceans) ;  because  ^the 
creature  can  only  possess  this  power  for  the  sake  of 
escaping  the  observation  of  its  foes.  If  we  believe  it 
to  be  so  provided  for  the  purpose  of  deceiving  its  prey, 
then  we  must  allow  the  existence  of  colour-perception 
even  in  more  lowly  forms  on  the  average  than  fishes  or 
Crustacea. 

Indeed,  the  brilliant  nature  of  many  marine  animals 
and  plants  affords  an  excellent  opportunity  for  the  de- 
velopment of  a  colour-sense.  Instead  of  the  uniform 
green  of  the  forest,  with  the  dingy  black  or  brown  of  soil 
and  rocks,  we  have  here  the  exquisite  colours  of  sea- 
anemones,  starfish,  corals,  serpulae,  jellyfish,  callianiridse, 
aphroditida3,  ascidians,  sea-slugs,  and  shell-covered  mollusca, 
which  browse  amid  groves  of  variegated  algae,  whose  hues 
are  far  more  diversified  than  those  of  terrestrial  veo-eta- 

o 

tion.  Amongst  such  surroundings  it  would  almost  be 
impossible  that  a  colour-sense  should  not  take  its  rise : 
and  many  indirect  proofs  conspire  to  show  that  in  the 
class  of  fishes  at  least  it  exists  in  high  perfection. 

The  most  striking  evidence  is  that  afforded  by  certain 
flat-fish,  which,  like  the  chameleon  shrimp,  possess  the 
power  of  changing  their  colour,  so  as  to  suit  the  bottom 
upon  which  they  lie.  Here  again  the  peculiarity  not  only 
shows  that  the  fish  themselves  are  differentially  affected 
by  the  various  colours,  but  also  that  their  enemies  or 
prey  are  conscious  of  similar  differences,  or  else  the  dis- 
guise would  be  useless. 

Equally  significant  is  the   colouration  of  the  common 


THE  COLOUR-SEXSE  IN  VERTEBRATES.         119 

sole,  brill,  dab,  and  flounder.  Any  person  who  has  seen 
these  fishes  lying  on  a  natural  bottom  or  in  an  aquarium 
must  have  been  struck  by  the  perfection  of  the  imitation, 
which  often  baffles  even  human  eyes,  in  spite  of  the 
actual  knowledge  that  a  fish  is  somewhere  to  be  found 
upon  the  spot. 

In  like  manner,  the  fishes,  mollusca,  and  crustaceans 
which  inhabit  the  sargasso  weed,  are  all  protectively 
coloured  of  exactly  the  same  pale  buff  hue  as  the  sargasso 
itself.  One  may  often  closely  examine  a  piece  of  the 
weed,  freshly  brought  up  in  a  bucket  of  sea- water,  and 
yet  fail  to  detect  any  sign  of  life,  until  the  attempt  to 
raise  the  weed  from  the  water  reveals  the  fact  that  some 
small  crabs  or  tiny  fishes  are  lurking  unseen  among  its 
waving  branches.  In  all  such  cases,  the  existence  of  the 
imitative  colouring  is  fair  proof  that  it  subserves  the  good 
of  the  species  by  protecting  its  members  against  enemies, 
or  enabling  them  more  readily  to  secure  their  prey. 

Perhaps  the  only  direct  evidence,  however,  is  that  of 
the  baits  used  by  fishermen.  Mackerel  and  other  fish  are 
often  taken  by  means  of  red  rags.  A  spoon  painted  bright 
scarlet  forms  a  capital  trolling  bait.  All  anglers  are 
agreed  that  trout  can  discriminate  between  the  various 
imitation  flies  offered  to  their  notice,  and  that  the  original 
colours  must  be  carefully  copied.  Indeed,  the  facts 
rather  tend  to  show,  not  only  that  fishes  can  discriminate 
colours,  but  also  that  they  are  attracted  by  metals  or  other 
brilliant  objects,  and  by  pure  or  intense  hues.  A  taste 
for  colour  as  w^ell  as  a  mere  neutral  perception  seems  to 
be  implied  by  these  observations. 

Those  who  have  given  the  greatest  attention  to  the 
subject  are  inclined  to  credit  fish  with  a  very  high  degree 
of  colour  sensibility ;  and  their  opinion  may  be  set  down 
here  as  having  some  weight  in  so  uncertain  a  subject. 
Mr.  H.  iST.  Mosely,  the  accomplished  naturalist  of  the 
Challenger  expedition,  believes  that  almost  all  the  colours 
of  marine  animals  have  been   acquired   for  purposes  of 


120  THE  COLOUR-SENSE. 

warning,  protection,  or  attraction  of  pre}^,  and  that  tliey 
have  special  reference  to  the  eyes  of  fishes  and  higher 
crustaceans.^  The  whole  colouration  of  the  lower  aquatic 
organisms  is  exactly  what  we  should  expect  it  to  be  if  the 
more  highly  evolved  marine  creatures  were  possessed  of 
a  colour-sense ;  and  it  is  quite  inexplicable  and  gratui- 
tously complex  if  we  suppose  them  to  be  destitute  of  such 
a  faculty.  Mr.  Darwin  is  farther  of  opinion  that  the 
colours  of  many  fishes  have  been  produced  by  the  action 
of  sexual  selection ;  and  though  I  do  not  mean  to  treat 
this  part  of  our  subject  in  detail  till  a  later  chapter,  I 
think  the  conclusion  of  so  careful  and  masterly  an  ob- 
server has  considerable  substantive  value  as  corroborative 
of  the  positive  facts. 

When  we  proceed  to  examine  the  amphibia,  much  better 
evidence  is  available.  The  two  colours  green  and  blue 
are  the  least  markedly  different  of  all  hues ;  and  if  they 
can  be  discriminated  from  one  another  by  any  species,  we 
may  be  sure  that  that  species  possesses  a  very  perfect 
form  of  colour-sense.  Kiihne  of  Heidelberg,  in  the  course 
of  certain  researches  on  the  nature  and  functions  of  retinal 
purple,  discovered  that  if  a  number  of  frogs,  Rana  esculenta 
and  R.  temporaria,  are  confined  in  a  shallow  dish,  one  half 
of  which  is  covered  with  oreen  c^lass  and  the  other  half 
with  blue,  they  will  shortly  all  collect  under  the  green 
portion.  Great  care  was  taken  to  eliminate  all  disturbing 
elements,  such  as  unequal  transparency  to  heat  (diather- 
mancy), or  unequal  intensity  of  illumination,  and  it  was 
conclusively  ascertained  that  an  enormous  majority  of  the 
frogs  exhibited  a  distinct  preference  for  the  colour  green 
over  the  colour  blue.  Blind  frogs  introduced  into  the 
same  vessel  showed  no  preference  for  one  part  over 
another.^  In  this  case,  again,  it  is  interesting  to  note 
that  a  special  emotional  taste,  as  well  as  an  intellectual 

^  Quarterly  Journal  of  Microsco-  -  Uutersuch.  aus  dem  Physiol.  In- 
pical  Science,  New  Series,  vol.  xvii.  stitut  iu  Heidelberg,  Band  i.  Heft  2. 
pp.  19,  22. 


THE  COLOUR-SENSE  IN  VERTEBRATES.        121 

discrimination,  is  proved  by  the  facts ;  and  tliis  taste 
becomes  particularly  interesting  from  the  point  of  view 
of  sexual  selection,  when  we  remember  that  green  forms  a 
very  common  colour  amongst  the  Ranidce, 

Frogs  likewise  possess  the  power  of  changing  their 
colour  in  correspondence  with  the  environment,  in  the 
same  manner  as  already  noted  in  Mysis} 

Eeptiles  also  show  some  distinct  marks  of  colour- 
perception.  The  most  familiar  instance  is  that  of  the 
chameleon,  whose  natural  hue  is  a  muddy  white,  changing 
with  the  nature  of  the  background  to  yellow,  brown, 
green,  or  bluish  grey.  The  mechanism  by  wliich  this 
change  is  effected  has  met  with  full  treatment  at  the 
hands  of  Von  Wittich.^  Two  layers  of  pigment  cells  are 
deeply  seated  under  the  skin,  consisting  of  blue  and 
yellow  colouring  matter  respectively ;  and  by  forcing  up 
one  or  other  of  these  layers  through  muscular  pressure, 
the  animal  assumes  a  bluish  or  yellowish  tint,  while  the 
green  is  produced  by  simultaneous  pressure  upon  both 
layers.  In  this  manner  the  chameleon  is  able  to  simulate 
the  appearance  of  the  branches  or  leaves  on  which  it 
stands,  and  so,  perhaps,  both  to  escape  enemies  and  de- 
ceive prey.  As  before,  the  power  of  changing  colour 
implies  impressibility  both  in  the  animal  itself  and  in 
certain  other  species  for  whose  deception  the  habit  has 
been  acquired.  The  action  is  undoubtedly  reflex,  and 
ceases  if  the  eyes  be  covered. 

Many  of  the  insects  which  mimic  leaves  or  other  like 
objects  in  the  environment  have  probably  gained  this 
means  of  protection  to  escape  the  notice  of  lizards  and 
other  reptiles.  But  as  the  mimetic  resemblance  is  oftener 
useful  for  deceiving  birds,  we  may  more  fitly  consider 
these  cases  when  we  pass  on  to  examine  the  colour-sense 
in  the  higher  vertebrates.     There  are  one  or  two  instances 

^  Pouchet,  Comptes  Rendus,  xxvi.  2  Proc.  Vienna  Imperial  Acad.  Nat. 
575,  and  Lister,  Phil.  Trans.,  148,  p_  Sci.,  vol.  iv.,  and  Miiller's  Archiv., 
627.  1854. 


122  THE  COLOUR-SENSE. 

of  protective  colouring,  however,  which  evidently  have 
reference  to  the  reptilian  eye  alone.  Mr.  Bates  mentions 
a  South  American  snake  {Dryopliis  fulgida),  whose  pale 
green  body  exactly  resembles  the  stem  of  a  liana,  and  even 
imposed  upon  the  keen-eyed  naturalist  himself  at  first 
sight.  The  prey  for  which  this  living  branch  lies  in  wait 
consists  of  tree-frogs  and  lizards.^  These,  themselves, 
in  turn,  may  perhaps  escape  it  by  their  own  prevailing 
greenness,  which  makes  them  so  difficult  of  detection 
amongst  the  foliage  on  which  they  rest.  Again,  Sir 
Joseph  Hooker  found  three  ticks  on  an  Indian  lizard, 
each  of  which  was  coloured  in  imitation  of  that  part  of  its 
host's  body  on  which  it  preyed.  One  from  the  yellow 
belly  was  yellow ;  one  from  the  brown  head  was  brown ; 
and  one  from  the  parti-coloured  scales  was  parti- coloured, 
"  the  hues  corresponding  with  the  individual  scales  which 
they  covered."  ^  Here  we  can  hardly  suppose  that  the 
imitation  could  be  of  any  use  except  as  a  protection 
against  the  lizard  himself  and  the  other  members  of  his 
family. 

It  may  be  worth  while  to  mention  in  passing  that  many 
lizards  besides  the  chameleons  possess  the  power  of  chang- 
ing their  colour  by  inflating  their  lungs,  which  compresses 
or  spreads  the  layers  of  pigment  cells.^  The  sexual  col- 
ours of  the  beautiful  Draco  and  other  reptiles  have  been 
fully  described  by  Mr.  Darwin.  "  The  shining  appendages 
of  the  throat,"  says  Dr.  Giinther,  "  are  merely  folds  of  the 
skin,  ornamental  and  sexual.  Such  appendages  always 
betray  an  excitable  temper,"  or,  in  other  words,  co-exist 
with  strong  sexual  jealousies.  The  significance  of  these 
facts  will  become  more  apparent  when  we  pass  on  to 
the  general  question  of  selective  preference  for  decorated 
mates. 

Among  birds,  the  perception  or  colour  is  shown  by  a 

^  The  Naturalist  on  the  Amazons,         '  Giinther,  Eeptiles  of  British  In- 
P-  99-  r'ia,  p.  56. 

2  Himalayan  Journal,  vol.  i.  p.  37. 


THE  COLOUR-SENSE  IN  VERTEBRATES.        123 

large  number  of  facts,  collected  by  Mr.  Darwin.^  A  tame 
partridge  described  by  Mr.  Hussey  "  seemed  fond  '  of  gay 
colours,  and  no  new  gown  or  cap  could  be  put  on  without 
catching  his  attention.'  "  ^  Lord  Lilford  notices  that  the 
ruff  "  will  dart  down  to  a  bright-coloured  handkerchief, 
regardless  of  rej)eated  shots."  ^  The  well-known  bower-bird 
"  collects  gaily  coloured  articles,  such  as  the  blue  tail- 
feathers  of  parrakeets,  bleached  bones,  and  shells."  Mr. 
Gould  "  found  in  one  bower  a  neatly  worked  stone  toma- 
hawk and  a  slip  of  blue  cotton."  "  The  regent-bird,  as 
described  by  Mr.  Eamsay,  ornaments  its  short  bower  with 
bleached  land-shells  belonging  to  five  or  six  species,  and 
with  berries  of  various  colours,  blue,  red,  and  black,  which 
give  it  when  fresh  a  very  pretty  appearance.  Besides 
these,  there  were  several  newly  picked  leaves  and  young 
shoots  of  a  pinkish  colour,  the  whole  showing  a  decided 
taste  for  the  beautiful."  * 

To  these  facts,  which  bear  evidence  to  taste  as  well  as 
perception,  we  may  add  the  antipathy  of  the  turkey-cock 
to  scarlet,  which  is  probably  an  effect  of  sexual  jealousy, 
as  the  red  would  be  ancestrally  associated  in  his  mind 
with  the  wattles  of  a  rival.  "  The  recognition  of  colour 
by  small  birds  generally,"  says  a  late  writer,^  ''  is  indis- 
putable. Every  one  must  have  observed  with  varied  feel- 
ings the  discrimination  with  which  they  select  the  '  sunny 
side '  of  a  pear,  a  plum,  or  a  peach.  It  is  also  an  esta- 
blished fact  that  they  will  attack  the  red  currant  in 
preference  to  the  white  variety,  though  the  latter  is  much 
the  sweeter  of  the  two.  Many  observers  during  the  last 
few  years  have  pointed  out  how  the  yellow  crocus  is  torn 
to  pieces  by  sparrows  and  other  birds,  while  the  white  and 
other   varieties    are   unmolested."     I   have  myself  often 

^  The  Descent  of  Man,   vol.  ii.  p.  Australia,  1865,  vol.  i.  pp.  444-461 ; 

no.  and   Ramsay,  in  "Tlie  Ibis,"  1867,  p. 

2  The  Zoologist,  1847-48,  p.    1602,  456,  quoted  in  Darwin,  uhi  sujora. 

quoted  in  Darwin,  w6i  sw/>ra.  ^  "  The    Senses     of     the     Lower 

2  "The  Ibis,"  vol.  ii.  p.  344,  i860.  Animals,"  in  the  Quarterly  Journal 

^  Gould,  Handbook  to  the  Birds  of  of  Science,  July  1878. 


124  THE  COLOUR-SENSE. 

noticed  in  Jamaica  the  unerring  certainty  Vvith  wliich 
chickens  darted  from  blossom  to  blossom  of  a  yellow 
potentilla,  for  which  they  have  a  particular  fancy,  and 
which  they  always  snapped  up  as  though  they  supposed 
it  to  be  alive. 

These  instances  lead  us  on  to  those  of  the  fruits,  whose 
development  we  examined  in  our  last  chapter.  "  Eed," 
says  Mr.  Wallace,  "  being  a  very  common  colour  of  ripe 
fruits  which  attract  birds  to  devour  them  and  thus  dis- 
tribute their  seeds,  we  may  be  sure  that  the  contrast  of 
red  and  green  is  to  them  very  marked."^  But  this  seems 
to  me  a  somewhat  inadequate  expression  of  the  real  evi- 
dence on  the  point.  We  have  seen  that  almost  all  those 
seeds  or  fruits  which  would  be  injured  by  the  interference 
of  birds  are  protectively  coloured  green  or  brown,  while 
almost  all  those  seeds  or  fruits  which  would  be  aided  by 
the  interference  of  birds  are  attractively  coloured  red, 
pink,  orange,  yellow,  purple,  blue,  lilac,  or  black.  I  think 
these  facts  fully  justify  us  in  concluding  that  birds  are 
able  to  distinguish  every  one  of  these  colours  from  green, 
and  most  likely  from  one  another.  Otherwise  there  would 
be  no  reason  why  succulent  fruits  should  differ  in  colour 
from  nuts.  The  single  case  of  the  almond  and  the  plum 
will  bring  the  question  at  issue  into  strong  relief.  As  in 
the  case  of  entomophilous  flowers,  so  in  the  case  of  succu- 
lent fruits,  unless  we  believe  that  the  seemingly  attractive 
organs  were  developed  for  the  purpose  of  enticing  animals, 
we  must  believe  that  they  are  a  positive  waste  of  energy 
to  the  parent  plant. 

The  evolution  of  bright  flowers  themselves  shows  that 
birds  as  well  as  insects  are  attracted  by  their  beautiful 
petals.  Mr.  Darwin  has  collected  many  instances  in 
which  blossoms  are  fertilised  by  birds ;  and  Fritz  MuUer 
notes  several  species  of  Ahutilon  in  Brazil,  which  he 
believes  depend  entirely  on  humming-birds  for  the  disper- 
sion of  their  pollen.^     Mr.  Wallace  observes  that  brilliant 

1  Tropical  Nature,  p.  246.  2  Cross-Fertilisation,  p.  371. 


THE  COLOUR-SENSE  IN  VERTEBRATES.        125 

flowers  witli  handsome  corollas  exist  in  many  Oceanic 
islands,  such  as  Juan  Fernandez,  where  flying  insects  are 
almost  unknown  ;  but  their  place  is  supplied  by  humming- 
birds, which  Mr.  Mosely  mentions  as  being  "  extraordinarily 
abundant."  ^  Mr.  Belt  believes  that  a  climbing  plant  of 
Central  America,  3f«'7-c9'ra  via  nepentlioides,  has  been  specially 
adapted  to  the  same  birds ;  while  Mr.  Wallace  thinks  that 
many  Australian  and  Malayan  flowers  have  been  similarly 
specialised  for  the  visits  of  honey-eaters,  lories,  and  sun- 
birds.  "Only  large  flowers,"  says  Mr.  J.  E.  Taylor,  "can 
be  visited  by  these  birds,  or  those  whose  polypetalous 
corollas  allow  of  the  head  being  thrust  into  the  centre. 
Hence  we  have,  in  some  measure,  a  reason  afforded  us  for 
the  laro^er  size  of  the  flowers  in  resjions  where  such  birds 
are  abundant.  The  large  bushes  and  trees  of  such  countries 
usually  bear  very  fine  showy  flowers  in  order  to  attract 
the  birds ;  and  it  is  found  that  the  brush-tongued  parra- 
keets  are  particularly  fond  of  the  flowers  which  grow  at  a 
height  above  the  ground."  ^  Any  one  who  has  watched  a 
humming-bird  darting  with  lightning  speed  from  blossom 
to  blossom  could  "hardly  have  a  doubt  of  his  acute  colour- 
perception. 

The  proofs  afforded  by  imitation  and  mimicry  are 
stronger  in  the  case  of  birds  than  of  any  other  class.  One 
may  say  generally  that  almost  all  insects  which  display 
protective  or  imitative  colouring  do  so  for  the  sake  of 
escaping  birds  or  lizards.  A  few  cases  must  suffice  to 
show  the  general  tendency  of  the  evidence.  The  leaf  and 
stick  insects  (Phylliidoe  and  Phasmidse)  closely  imitate  the 
colours  and  shapes  of  leaves  and  sticks.  One  in  particular, 
the  Ceroxylus  laceratus,  is  apparently  overgrown  by  moss 
or  jungermaunia.^      Sir  Emerson  Tennent  describes  the 

1  Tropical  Nature,  p.  273.  ^'^^  the  omission  would  have  been  a 

2  Flowers,  their  Origin,  &c.,  p.  serious  defect;  sol  have  here  departed 
294.  This  is  the  only  instance  in  from  my  usual  rule,  and  taken  most 
which  I  have  availed  myself  of  new  of  the  above  cases  from  Mr.  Taylor's 
matter   from    this   interesting  little  pages. 

volume,  which  appeared  while  I  was        '  Wallace,    Contributions    to    the 
\n  course  of  revising  my  manuscript ;    Theory  of  Natural  Selection,  p.  64. 


126  THE  COLOUR-SENSE. 

leaf-insects  as  possessing  "  all  varieties  of  hue,  from  the 
pale  yellow  of  an  opening  bud  to  the  rich  green  of  the 
full-blown  leaf  and  the  withered  tint  of  decay."  ^  The 
Kallima  paraleJcta,  a  leaf-like  butterfly  of  the  Malay 
Archipelago,  always  rests  among  dead  or  dry  leaves,  which 
it  resembles  in  all  their  varying  hues,  even  appearing  to 
be  spotted  with  small  fungi.  Canon  Tristram  has  noted 
that  almost  every  insect,  bird,  or  reptile  inhabiting  the 
desert  of  Sahara  is  coloured  exactly  like  sand,-  and  Lord 
George  Campbell  mentions  a  butterfly  similarly  imitative 
of  its  background  which  frequented  the  sea-shore  at  Am- 
boyna.^  A  South  American  Zeptalis  so  closely  resembles 
an  uneatable  Ithomia  "in  every  shade  and  stripe  of  colour," 
that  Mr.  Bates  could  hardly  distinguish  them,  even  with 
the  aid  of  his  minute  entomological  knowledge.  *'  One  of 
the  Hemiptera  (Spiniger  luteicornis),"  says  Mr.  Belt,  "  had 
every  part  coloured  like  the  hornet  {Priocnemis)  that  it 
resembled.  In  its  vibrating  coloured  wing-cases  it  departed 
greatly  from  the  normal  character  of  the  Hemiptera  and 
assumed  that  of  the  hornets."  *  The  same  careful  observer 
gives  many  similar  instances  of  mimetic  resemblance  in 
the  Coleoptera,^  and  Lepidoptera.^  But  perhaps  the  most 
astonishing  of  these  imitative  forms  is  that  of  a  moss-like 
insect,  the  larva  of  a  Phasma,  which  is  prolonged  into 
curious  green  filaments,  to  mimic  the  moss  in  which  it 
lives.'^  Of  course  these  creatures  could  derive  no  advantage 
from  their  minute  reproduction  of  spots,  lines,  and  hues, 
unless  the  enemies  against  which  they  required  protection 
were  capable  of  distinguishing  their  colours. 

Mimicry  or  imitative  devices  of  this  sort  are  not  confined 
to  insects.  Many  lizards,  such  as  the  geckos,  have  colours 
like  those  of  the  walls  on  which  they  creep ;  while  the 

1  Ceylon,  j).  251.  authority,  lie  may  be  confidently  relied 

2  See  also  Gurney,   Kambles    of  a     on  for  any  question  of  fact. 
Naturalist,  p.  56.  ^  The  Naturalist  in  Nicaragua,  p. 

^  Log-letters  from  the  Challenger,     319. 
p.  208.    Although  this  amusing  writer        ^  Ibid.,  p.  317.  ^  P.  382. 

can  hardly  be  considered  a  scientific        '  Figured  in  Belt,  ubi  supra,   p. 

382. 


THE  COLOUR-SENSE  IN  VERTEBRATES.        127 

protective  green  hue  of  the  tree-frogs  has  already  been 
noticed.  Even  birds  occasionally  mimic  one  another  in 
the  same  manner.  For  example,  two  species  of  Mimeta 
(a  sort  of  oriole),  in  Bouru  and  Ceram,  imitate  two  Tropi- 
dorhynclii  (honeysuckers)  in  minute  details  of  colour, 
thus  escaping  small  birds  of  prey,  as  the  Tropidorhynchi 
are  strong  and  pugnacious  creatures.-^  For  other  cases 
the  reader  must  be  referred  to  Mr.  "Wallace's  admirable 
essay  on  "  Mimicry  and  other  Protective  Eesemblances 
among  Animals." 

These  various  proofs,  though  indirect,  can  leave  us  in 
little  doubt  with  regard  to  the  general  existence  of  a 
colour-sense  among  birds. 

"When  we  come  to  the  highest  class  of  vertebrates — the 
mammalia — strangely  enough  the  evidence  of  a  colour- 
sense  almost  entirely  fails  us.  The  antipathy  of  male 
ruminants  for  scarlet,  and  the  curiosity  which  certain 
monkeys  display  with  regard  to  bright-coloured  objects, 
are  the  only  facts  in  point  which  come  under  ordinary 
observation.  This  result,  so  contrary  to  what  we  might 
have  expected,  appears  really  quite  natural  when  we  exa- 
mine more  closely  the  circumstances  of  the  case.  By  far 
the  larger  part  of  the  mammalia  are  either  herbivorous 
like  the  ruminants  and  pachyderms,  or  carnivorous  like 
the  technical  carnivores,  insectivores,  and  whales.  Only 
a  small  portion  of  the  class  subsists  upon  fruits,  w^hile 
none  of  them  are  very  specially  connected  with  flowers. 
Hence  a  large  set  of  possible  tests  which  we  can  employ 
in  the  case  of  insects  and  birds  are  wholly  inapplicable  to 
mammals.  Moreover,  the  want  of  close  relations  with  the 
coloured  parts  of  plants  has  probably  resulted  in  a  want 
of  any  peculiar  love  for  bright  colour,  such  as  we  see 
reason  to  suspect  in  the  butterflies,  humming-birds,  and 
parrots.  This  absence  of  a  taste  for  brilliancy  is  probably 
marked  by  the  absence  of  brilliant  hues  in  the  animals 
themselves,  the  result  of  sexual  selection ;  for  these  hues, 

•■  Wallace,  Malay  Archipelago,  p.  401. 


128  THE  COLOUR-SENSE. 

as  we  shall  see  hereafter,  only  appear  among  the  mam- 
malia in  a  few  higher  arboreal  and  frugivorous  species, 
such  as  the  mandrill  and  certain  squirrels.  For  the  most 
part,  throughout  the  mammalian  series  sexual  selection 
seems  only  to  have  exerted  itself,  if  at  all,  in  the  produc- 
tion of  elegant  shapes,  protuberances  like  horns  and  dew- 
laps, and  marked  contrasts  of  light  and  shade,  as  in  the 
zebra,  giraffe,  and  hysena. 

Nevertheless  we  can  hardly  doubt  that  mammals  do 
possess  a  considerable  colour-sense,  though,  owing  to  the 
circumstances  of  their  practical  environment,  their  taste 
for  any  special  hue  is  probably  far  from  strong. 

Here  once  more  I  must  remind  the  reader  that  the 
proofs  of  a  colour-sense  throughout  the  whole  infra-human 
world  are  necessarily  very  derivative,  and  that  they  owe 
their  chief  strength  to  their  cumulative  character.  The 
fragmentary  evidence  collected  in  this  chapter  will  be 
much  corroborated  and  supplemented  by  that  which  will 
be  detailed  in  the  sequel.  Enough  will  have  been  done  if 
we  succeed  in  showing  that  the  hypothesis  of  a  general 
colour-sense  is  consonant  with  all  the  facts  of  nature,  and 
helps  us  to  understand  those  facts  in  a  way  which  no  other 
hypothesis  can  do.  '  For  the  present  it  will  be  sufficient  if 
we  bear  in  mind  the  one  great  point  hitherto  settled — that 
wherever  any  part  of  a  plant,  be  it  flower  or  fruit,  will 
derive  any  benefit  from  attracting  the  eye  of  an  animal,  be 
it  insect,  bird,  or  mammal,  that  part  is  almost  invariably 
coloured  with  some  pure  and  brilliant  hue,  be  it  blue,  red, 
yellow,  pink,  orange,  violet,  or  lilac,  quite  distinctive  from 
the  green  of  ordinary  vegetation.  This  one  fact  is  the 
great  pivot  upon  which  turns  our  whole  knowledge  of  the 
animal  colour-sense.  


(    129    ) 


CHAPTER  VIII. 

THE   COMMUNITY   OF   TASTE   BETWEEN    FLOWER- 
FEEDING  AND   FRUIT-EATING   SPECIES. 

Before  we  proceed  to  consider  the  secondary  reactions  of 
the  colour- sense  in  insects  and  vertebrates  upon  their  own 
external  appearance,  we  must  glance  for  a  moment  at  one 
of  the  determining  causes  which  give  approximate  unifor- 
mity to  the  general  results  of  such  reactions  in  the  animals 
with  which  we  are  most  specially  concerned.  In  the  next 
chapter  we  shall  have  to  examine  the  production  of  bright 
hues  in  the  wings  of  butterflies,  the  skins  of  lizards,  the 
feathers  of  birds,  and  the  fur  of  mammals,  due  to  the 
selective  action  of  sexual  preferences.  But,  as  a  necessary 
preliminary  to  that  inquiry,  we  must  first  set  ourselves  to 
determine  the  principles  which  govern  the  formation  of 
tastes  generally  among  the  flower-feeding  and  fruit-eating 
animals.  Before  we  can  trace  to  its  final  effects  the  action 
of  a  sexual  preference  for  bright  colouring,  we  must  pre- 
viously find  out  with  certainty  the  reasons  why  a  taste 
for  such  colouring  should  exist  at  all  in  the  animal  con- 
sciousness. 

People  are  generally  too  apt  to  accept  as  ultimate  and 
obvious  every  fact  with  which  they  have  always  been 
familiar.  Seeing  that  bright  colours  as  a  rule  attract  chil- 
dren and  savages,  dogs,  birds,  fish,  and  insects,  they  do  not 
trouble  themselves  to  seek  a  reason  for  this  preference, 
but  take  it  for  granted  as  an  inherent  and  natural  pro- 
perty of  the  animal  organism,  or,  more  often  and  more 
absurdly  still,  of  the  colours  themselves.     If,  however,  we 

I 


I30  THE  COLOUR-SENSE. 

reflect  upon  the  subject  for  a  moment,  we  shall  see  that 
there  is  no  primitive  and  self-sufficing  reason  in  the  nature 
of  things  why  anj^  one  colour  should  be  more  beautiful  to 
us  than  another.  Dull  and  dingy  hues  might  conceivably 
have  been  just  as  pleasant  to  our  sense,  under  slightly 
different  conditions  of  our  development,  as  we  know  bright 
and  pungent  hues  to  be,  under  the  actual  circumstances  of 
humanity.  We  must  get  a  little  deeper  into  the  ground- 
work of  our  likes  and  dislikes  if  we  would  really  under- 
stand the  origin  of  our  native  preference  for  brilliant  tints 
over  mixed  or  unstimulating  colours. 

Now,  after  this  preamble,  most  readers  will  imagine 
that  I  mean  to  explain  the  liking  of  flower-feeders  and 
fruit- eaters  for  bright  hues  by  means  of  that  grand  but 
somewhat  vaguely  employed  shibboleth,  the  Association 
Theory.  I  know  that  to  the  mass  of  loose  thinkers  associa- 
tion is  a  sort  of  psychological  dms  ex  7nachinawh.ic]i  satisfac- 
torily accounts  for  every  ill-defined  mental  problem,  just  as 
electricity  is  a  sort  of  physical  deus  ex  machina  which  simi- 
larly gets  over  every  ill-comprehended  material  problem. 
Such  persons  say  to  themselves  at  once,  "  Oh,  of  course, 
birds  and  butterflies  feed  off  bright-coloured  objects ;  so 
bridit  colours  f^et  associations  with  their  food,  and  are 
consequently  pleasant  to  them."  Having  thus  satisfied 
their  nascent  critical  doubts  by  the  easy  application  of  an 
accepted  formula,  they  never  pause  to  translate  their  vague 
speculation  into  thinkable  terms,  but  leave  it  as  they  took 
it  up,  a  mere  algebraical  expression,  incapable  of  rational 
statement  in  a  concrete  form.  For  how  can  association 
with  food  make  a  colour  or  anything  else  pleasant  in  itself  ? 
This  is  the  true  crux  of  the  Association  Theory,  a  crux 
which,  as  I  humbly  believe,  few  of  its  adherents  have  ever 
perceived  in  its  full  significance.  Until  it  has  been  solved, 
the  theory  remains  a  mere  verbal  explanation,  adding  no- 
thing to  our  real  knowledge  of  the  subject,  yet  deluding 
us  by  its  specious  resemblance  to  an  explanatory  truth. 

The  mode  of  exposition  here  adopted  will  be  a  very 


COMMUNITY  OF  TASTE.  131 

different  one,  based  upon  the  known  psyclio-pliysical  law 
of  pleasure  and  pain.  According  to  that  law,  pleasure  is 
the  psychical  aspect  of  an  ultimate  physiological  fact, 
which  in  its  physical  aspect  may  be  summed  up  as  the 
unimpeded  activity  of  a  fully  nurtured  and  not  over- 
worked nervous  structure  in  unbroken  connection  with 
the  cerebro-spinal  or  other  central  sentient  system.  Con- 
versely, or  nearly  so,  pain  is  the  psychical  aspect  of  an 
ultimate  physiological  fact,  which  in  its  physical  aspect 
may  be  summed  up  as  the  disintegration,  insufficient  nutri- 
tion, or  excessive  activity  of  a  nervous  structure,  similarly 
connected  with  the  sentient  organism.^  With  the  latter 
half  of  this  important  law  we  have  here  little  or  nothing 
to  do ;  but  the  former  half  so  intimately  concerns  our 
subject  that  I  shall  make  no  apology  for  endeavouring 
briefly  to  explain  its  meaning  in  simpler  language  than 
that  of  the  above  abstract  formula. 

A  pleasure,  then,  is  the  feeling  which  results  when  any 
sentient  nervous  centre  receives  a  stimulation  not  exces- 
sive in  quantity,  nor  beyond  the  existing  power  of  the 
structures  concerned.  Every  centre  undergoes  at  each 
stimulation  a  certain  amount  of  disintegration ;  and  if  that 
disintegration  pass  beyond  the  easy  repairing-point  of  the 
system,  pain  sets  in.  But,  on  the  other  hand,  so  long  as 
the  stimulation  is  moderate,  by  exercising  the  structures  it 
promotes  their  general  efficiency,  and  hence  it  is  accom- 
panied by  a  feeling  of  pleasure.  Or  to  translate  our  law 
into  still  more  concrete  and  ordinary  language,  we  may 
say  that  whenever  an  organ  which  can  feel  at  all  is  exer- 
cised not  beyond  the  due  amount,  pleasure  is  the  result. 
Hence  the  pleasurableness  of  any  activity  may  be  ac- 
cepted as  a  rough  gauge  of  its  general  desirability  for  the 
organism    as  a  whole,  while  conversely  its   painfulness 

1  For  a  full  explanation  of  the  form  wards),  see  my   "Physiological  ^Es- 

here  given  to  this  law  (originally  due  thetics,"    chap,    ii.,    "Pleasure   and 

to  Mr.  Herbert  Spencer  and  Professor  Pain,"  where  the  grounds  upon  which 

Bain,  working  on  the  basis  of  previ-  the  conclusion  is  based  have  been  de- 

OU3  inquirers,  from  Aristotle  down-  tailed  at  length. 


132  THE  COLOUR-SENSE. 

may  be  regarded  as  a  certain  proof  of  its  general  unde- 
sirability. 

]^ow  the  more  fully-nurtured  an  organ  mayj  be,  tlie 
higher  is  its  functional  efficiency,  and  the  greater  the  plea- 
sure to  be  derived  from  its  exercise.  We  all  know  that 
the  fresher  our  limbs,  our  muscles,  our  nerves,  and  our 
eyes,  the  greater  the  enjoyment  we  derive  from  a  country 
walk  or  a  game  of  cricket.  After  long  fasting  we  eat  our 
food  with  greater  relish ;  after  long  confinement  we  use  our 
less  and  arms  with  redoubled  delio-ht.  But  we  also  know 
that  in  order  to  keep  up  a  state  of  high  efficiency  in  any 
organ,  frequent  exercise  is  necessary.  Only  by  running, 
jumping,  rowing,  and  gymnastics  can  we  bring  our  muscles 
into  a  proper  condition  for  hard  athletic  work.  Only  by 
constant  practice  can  we  retain  any  accomplishment  which 
we  have  learnt  by  dint  of  serious  effi)rt.  And  just  the 
same  is  true  of  nerves.  Their  existing  structure  has  been 
acquired  by  continuous  function  in  past  generations,  and 
continuous  function  is  necessary  still  if  we  would  prevent 
them  from  rusting  into  obsolescence. 

Accordingly,  whenever  we  find  that  any  activity  is  pro- 
ductive of  immediate  pleasure  in  ourselves,  we  may  be  sure 
that  the  activity  in  question  is  one  which  has  long  been 
practised  by  our  human  or  ante-human  ancestors.  The 
greater  the  pleasure,  as  I  have  elsewhere  endeavoured  to 
show,  the  greater  the  intimacy  of  connection  between  the 
activity  and  the  life  of  the  species.  Let  us,  for  example, 
take  the  case  of  colour  itself,  with  which  we  are  here  so 
fully  engaged.  If  in  any  species  the  need  for  distinguish- 
ing different  colours  ever  arose,  and  if  by  its  side  there  also 
arose  a  nascent  structure  for  so  distinguishing  them,  then 
those  individuals  in  which  that  structure  was  most  fully 
developed  would  survive  from  generation  to  generation,  in 
virtue  of  their  superior  adaptation  to  the  needs  of  their 
environment  above  their  less  highly  endowed  compeers. 
But  with  each  such  increment  in  the  structure  there  would 
go  increased  pleasure  in  the  function.     Conversely,  the 


COMMUNITY  OF  TASTE.  133 

more  fully  the  function  was  indulged  the  more  would  the 
structure  increase  and  strengthen  by  exercise.  So  from 
generation  to  generation,  as  the  power  of  distinguishing 
colours  became  more  and  more  developed,  the  pleasure 
arising  from  their  perception  would  grow  more  and  more 
acute.  Such  pleasure  forms  the  first  groundwork  for  that 
differential  preference  in  individuals  or  species  which  we 
Know  as  taste. 

But  every  colour  would  not  probably  prove  equally 
pleasurable.  Some,  like  the  ordinary  greys,  greens,  and 
browns,  occur  too  often  in  the  surrounding  world  to  allow 
of  any  marked  gratification,  derivable  only  from  the  in- 
termittent stimulation  of  little-worked  nerves.  Moreover, 
these  common  colours  would  have  no  special  reference  to 
the  life  of  the  race,  and  so  would  have  few  structural  con- 
nections with  other  portions  of  the  central  nervous  system. 
But  in  the  case  of  fruit-eating  and  flower-feeding  species, 
we  may  well  suppose  that  the  special  nerves  devoted  to 
the  perception  of  red,  yellow,  orange,  and  purple  would 
naturally  be  much  strengthened  by  constant  hereditary 
use ;  while  the  comparatively  intermittent  nature  of  the 
stimulation  would  render  the  accompanying  feeling  far 
more  pleasurable  than  in  the  more  familiar  instances  of 
green  or  brown.  Furthermore,  the  close  relation  of  these 
colours  with  the  food  of  the  species  would  doubtless  give 
rise  to  numerous  nervous  connections  in  the  central  sys- 
tem, whereby  the  sight  of  such  coloured  objects  might  set 
up  the  necessary  movements  for  obtaining  the  booty.  In 
this  manner  the  central  organs  of  special  colour-percep- 
tion for  the  brilliant  hues  of  fruits  and  flowers  would  in 
all  probability  assume  unusually  large  dimensions,  and 
would  certainly  possess  large  numbers  of  concurrent  fibres 
along  which  waves  of  discharge  might  readily  travel,  thus 
giving  free  vent  for  a  considerable  volume  of  pleasure- 
yielding  energy.  Such  species  might  fairly  be  said  to 
possess  a  taste  for  red,  yellow,  and  other  like  pungent 
hues ;  and  we  might  accordingly  give  a  rough  definition 


134  THE  COLOUR-SENSE. 

of  taste  as  a  special  preference,  in  an  individual  or  a  race, 
for  one  or  more  out  of  several  similar  objective  stimuli, 
depending  ultimately  upon  special  variations  of  nervous 
development. 

Of  course  this  hasty  definition  leaves  out  of  considera- 
tion the  other  half  of  the  subject,  which  we  might  perhaps 
sum  up  as  distaste, — the  special  repugnance  to  one  or 
more  among  such  stimuli,  ultimately  due  to  like  diversi- 
ties of  individual  or  generic  organisation.  In  this  case, 
however,  we  must  distinguish  between  two  widely  dif- 
ferent forms  of  feeling,  which  are  apt  at  first  to  be  men- 
tally confused, — mere  neutral  indifference,  which  results 
from  a  stimulation  too  languid  or  too  common  to  produce 
pleasure,  and  positive  dislike  or  disgust,  which  arises 
from  some  actually  painful  and  disintegrative  action. 
Thus,  in  sight,  an  ugly  colour,  like  that  of  mud,  is  simply 
neutral  and  unstimulating ;  but  in  taste,  a  bitter  or  acrid 
substance  probably  sets  up  material  disintegration,  and  so 
of  course  produces  a  positively  painful  sensation.  This 
distinction  will  become  more  obvious  and  more  important 
as  we  proceed. 

In  this  way  only,  then,  as  it  seems  to  me,  can  associa- 
tion have  anything  to  do  with  the  intrinsic  pleasurable- 
ness  of  any  sensation,  namely,  by  affording  outlets  for 
the  overflowing  nervous  energy.  But  the  main  pleasure 
of  the  sensation  itself,  as  I  understand  the  question,  must 
be  due  to  inherited  cahbre  of  the  nerves  and  nervous 
centres  employed,  that  calibre  being  due  itself  to  ances- 
tral function  throughout  many  previous  generations.  To 
put  once  more  the  concrete  case,  fruit-eaters  and  flower- 
feeders  derive  pleasure  from  brilliant  colours  (postulating 
the  fact  for  the  time  being,  argumenti  gratia),  not  because 
those  colours  have  mental  associations  with  their  food, 
but  because  the  structures  which  perceive  them  have  been 
continually  exercised  and  strengthened  by  hereditary  use. 
The  connection  with  food  has  given  numerous  outlets  for 
the  nervous  energy,  and  has  been  the  ultimate  cause  for 


COMMUNITY  OF  TASTE.  135 

the  extra  development  of  colour-perceiving  structures, 
but  it  has  had  no  direct  effect,  as  I  believe,  upon  the 
immediate  pleasure  of  sensation. 

It  is  true  that  in  highly  evolved  animals,  with  whom 
the  emotions  have  attained  an  immense  and  preponderant 
influence,  associations  do  largely  enter  into  all  pleasur- 
able feelings.  But  even  here  the  ultimate  explanation 
is  equally  simple  and  straightforward.  These  emotions 
have  their  own  proper  nervous  seats,  as  Terrier's  experi- 
ments sufficiently  show ;  and  we  must  suppose  that  the 
actual  sensation,  being  located  in  a  centre  which  has  con- 
nections with  the  seats  of  such  emotions,  rouses  action  in 
the  emotional  centres,  more  or  less  conspicuously,  and  so 
adds  a  more  or  less  distinct  factor  to  the  total  resulting 
consciousness.  But  it  would  be  very  foolish  to  transfer 
similar  ideas  into  the  simple  nervous  organisation  of 
birds,  and  still  more  into  that  of  bees  and  butterflies. 
Taste  in  these  animals  must  be  almost  entirely  a  matter 
of  direct  sensation,  dependent  upon  the  calibre  of  the 
nerves  employed,  and  little  influenced  by  the  few  possible 
associated  feelings.^ 

Having  premised  these  few  considerations  as  to  the 
nature  of  taste  in  general,  let  us  now  go  on  to  examine 
the  special  tastes  of  fruit-eating  and  flower-feeding  ani- 
mals. We  shall  find  on  investigation  that  these  appear  to 
be  approximately  identical  throughout  the  whole  animal 
series ;  while  they  are  more  or  less  strongly  marked  off' 
from  the  opposite  tastes  of  carnivores  and  carrion-eaters. 
The  very  same  sweet  and  sugary  substances,  the  very 
same  etherial  and  delicate  perfumes,  the  very  same  bright 

1  Lest  any  reader  should  imagine  that   I  begin  to  dissent ;  and  even 

that  I  mean  by  these  remarks  to  cast  here    my   dissent,   as   will     be     seen 

some  doubt  upon  the  whole  body  of  from   the  above  paragraph,  extends 

Associationist  Psychology,    I  hasten  only  to  the  very  simplest  elements  of 

to  add,  parenthetically,  that  I  fully  feeling.      I    do    not   for   a   moment 

accept  that  system  so  long  as  it  con-  doubt  that  the  a3sthetic  pleasures  of 

fines  itself  to  the   relation  between  cultivated  Aryan  man  depend  largely, 

the  senses  aud  the  intellect.     It  is  or  even  mainly,  upon  associated  emo- 

only  when  it  is  brought  forward  as  a  tion. 
verbal  explanation  of  emotional  facts 


136  THE  COLOUR-SENSE. 

and  dainty  colours,  seem  pleasing  in  the  very  same  way  to 
butterflies,  and  humming-birds,  and  parrots,  and  apes,  and 
men.  The  similarity  of  nervous  impressibility  which  we 
thus  perceive  to  hold  throughout  the  whole  heterogene- 
ous collection  of  fruit  and  flower  haunters  casts  much  light 
upon  the  nature  of  sexual  selection,  and  upon  the  identity 
of  taste  between  man  and  so  many  lower  animals.  It 
enables  us  to  see  why  the  flowers  which  the  bee  de- 
veloped for  his  own  delight  and  guidance  should  be  the 
joy  of  children  and  the  envy  of  artists ;  why  the  hues  of 
the  orange  and  the  mango  should  be  as  beautiful  to  man 
as  to  the  toucans  and  macaws  which  gave  them  origin ; 
why  the  wing  of  the  butterfly,  the  tail  of  the  peacock, 
and  the  burnished  throat  of  the  sun-bird  should  be  exqui- 
site to  our  eyes  as  they  were  to  those  of  their  fastidious 
mates ;  and  why  human  beings  should  dye  their  bodies 
with  the  woad  of  Britain  and  the  ochre  of  Papua,  or  tinge 
their  garments  with  the  purple  of  Tyre  and  the  thou- 
sand hues  of  Lyon,  to  vie  with  the  gorgeous  tints  of  bird 
and  insect  in  the  very  self-same  profusion  of  refulgent 
colours. 

First,  then,  let  us  begin  with  the  sense  of  tasU.  It  is 
a  most  noteworthy  fact  that  wherever  any  part  of  a  plant 
can  gain  any  advantage  by  attracting  the  notice  of 
animals,  it  always  effects  its  purpose  by  the  secretion  of 
sugar,  or,  as  we  oftener  though  more  incorrectly  call  it  in 
this  connection,  honey.  Now  sugar,  as  I  have  already 
pointed  out,  has  a  special  power  of  acting  upon  the 
gustatory  nerves  of  animals,  through  the  great  solubility, 
diffusibility,  and  crystalline  texture  of  its  particles.  Ac- 
cordingly, we  find  that  almost  all  classes  of  fruit-eaters 
and  flower-feeders  show  a  decided  partiality  for  this 
pleasant  stimulant — a  partiality  due,  doubtless,  to  the 
long  habits  of  their  ancestors,  which  have  developed  cor- 
respondingly differentiated  structures  for  the  perception 
of  the  particular  body  in  question.  In  flowers,  sugar  is 
secreted  to  attract  bees  and  other  insects ;  while  in  fruits, 


COMMUNITY  OF  TASTE.  137 

it  acts  as  an  allurement  to  birds  and  mammals.  Further- 
more, certain  plants  possess  organs  for  the  secretion  of 
sugar  on  their  stems  or  at  the  base  of  their  leaf-stalks,  of 
which  Sir  John  Lubbock  gives  the  following  account : — 
"  Belt  and  Delpino  have,  I  think,  suggested  the  true  func- 
tion of  these  extra-floral  nectaries.  The  former  of  these 
excellent  observers  describes  a  South  American  species 
of  Acacia,  which,  if  unprotected,  is  apt  to  be  stripped  of 
its  leaves  by  a  leaf-cutting  ant,  which  uses  the  leaves  not 
directly  for  food,  but,  according  to  Mr.  Belt,  to  grow 
mushrooms  on.  The  Acacia,  however,  bears  hollow 
thorns,  and  each  leaflet  produces  honey  in  a  centre-formed 
gland  at  the  base,  and  a  small  sweet  pear-shaped  body  at 
the  tip.  In  consequence,  it  is  inhabited  by  myriads  of  a 
small  ant  which  nests  in  the  hollow  thorns,  and  thus  finds 
meat,  drink,  and  lodging  all  provided  for  it.  These  ants 
are  continually  roaming  over  the  plant,  and  constitute  a 
most  efficient  bodyguard,  not  only  driving  off  the  leaf- 
cutting  ants,  but  even,  in  Mr.  Belt's  opinion,  rendering 
the  leaves  less  liable  to  be  eaten  by  herbivorous 
mammalia."  ^  Indeed,  so  universal  is  the  taste  for  suo'ar 
among  insects,  that  certain  small  animal  creatures,  like 
the  Aphides  and  Cocci,  have  themselves  acquired  the 
habit  of  developing  nectaries,  and  so  gaining  the  protection 
of  ants,  which  may  be  seen  "  assiduously  running  up  the 
stems  of  plants  to  milk  these  curious  little  cattle."  And 
if  we  want  further  proof  of  the  general  love  for  sweet  food- 
stuffs, we  need  only  bethink  us  how  the  insects  flock  about 
a  barrel  of  treacle  in  our  streets,  how  the  birds  cono-re^-ate 
in  fruit-gardens,  and  how  our  own  children  gather  around 
the  windows  of  the  confectioner's  shop  to  stare  at  the 
tempting  wares  within — rendered  all  the  more  enticing, 
be  it  observed,  through  the  very  same  addition  of  red,  blue, 
and  yellow,  which  had  already  been  invented  by  the  fruit 
and  the  flower. 

1  "  On  Certain  Eelations  between  Plants  and  Insects,"  a  lecture  delivered 
at  Glasgow,  January  24,  1878,  p.  6. 


138  THE  COLOUR-SENSE. 

Equally  significant  are  the  changes  in  habit  or  mode  of 
life  between  fruit-eating  and  flower-feeding  classes.  Thus, 
a  large  number  of  hymenopterous  insects  live  upon  honey 
extracted  from  flowers ;  but  the  omnivorous  wasps,  as  we 
all  know,  have  taken  to  surreptitious  feasting  upon  the 
sugary  juices  of  peaches,  pears,  and  nectarines.  In  like 
manner,  I  have  often  noted  lepidopterous  species,  whose 
natural  food  consists  of  the  nectar  in  summer  blossoms, 
feeding  greedily  upon  fallen  fruit.  Mr.  W.  M.  Gabb 
captured  the  lovely  Morplios  of  Nicaragua  by  baiting  with 
a  piece  of  over-ripe  banana ;  ^  and  the  Eev.  J.  G.  Wood,  a 
most  trustworthy  recorder  in  all  that  concerns  the  habits 
of  animals,  notices  on  one  occasion  having  seen  whole 
hordes  of  the  Eed  Admiral  butterfly  ( Vanessa  atalanta) 
darkening  the  ground  wdiere  a  number  of  egg-plums  lay 
beneath  their  parent  tree.^  So,  too,  amongst  birds ;  while 
most  of  them  take  their  sugary  food  in  the  form  of  fruit 
or  seeds,  a  few  kinds,  like  humming-birds  and  sun-birds, 
live  largely  off  the  nectar  of  flowers,  mixed  with  the  insects 
which  frequent  them.^  Mr.  Webber,  an  American  natura- 
list, tried  the  experiment  of  taming  the  pretty  little 
ruby-throats,  which  he  fed  on  syrup  alone,  and  though 
he  found  that  they  could  not  thrive  without  a  fair  pro- 
portion of  insects  as  well,  he  also  discovered  that  they 
showed  a  decided  partiality  for  the  taste  of  sugar. 
"  Some  which  had  been  thus  tamed  and  set  free  returned 
the  following  year,  and  at  once  flew  straight  to  the  re- 
membered little  cup  of  sweets."  ^  In  certain  instances,  we 
find  the  interchange  of  habit  taking  place  within  the 
limits  of  a  single  tribe.  Thus,  the  true  parrots  live  al- 
most entirely  off  sweet  fruits,  but  their  congeners  the  lories 
are  nectar-eaters.  These  facts,  once  more,  we  may  cor- 
relate with  well-known  human  habits ;  as  when  we  see 
children,  whose  taste  for  sweets  is  derived  from  frugi- 

^  "  Nature,"  February  7,  1878.  see  Wallace,  "  Tropical  Nature,"  p. 

2  "Insects  at  Home,"  p.  401.  235. 

2  Ou  the  food  of   humming-birds,        ■^  Ibid.,  p.  137. 


COMMUNITY  OF  TASTE.  139 

vorous  ancestors,  sucking  the  juices  of  honeysuckle  and 
clover,  or  stealing  the  honey-bag  from  our  domesticated 
hive-bees.  Indeed,  we  could  have  no  more  simificant 
symbol  of  the  community  of  nature  here  pointed  out 
than  the  fact  that  we  keep  these  same  bees  to  gather 
honey  for  us  from  the  nectaries  of  flowers. 

Conversely,  whatever  parts  of  a  plant  would  be  injured 
by  the  interference  of  animals,  secrete  a  bitter  or  acrid 
juice,  which  acts  deleteriously  upon  the  nerves  of  taste. 
Thus,  as  I  have  already  pointed  out,  the  pericarp,  which 
in  fruits-proper  is  provided  with  sugary  secretions,  in 
nuts  is  commonly  stored  with  a  nauseous  principle  as  a 
deterrent  to  animal  foes.  Again,  those  fruits  which  have 
a  sweet  pulp  generally  guard  against  the  loss  of  their 
actual  seeds  by  filling  them  with  a  bitter  substance,  of 
which  prussic  acid  often  forms  a  leading  constituent : 
cases  occur  in  the  peach-stone,  the  apple-pip,  and  the 
seeds  of  oranges  or  mangoes.  That  animals  as  a  rule  dis- 
like bitter  substances  is  a  matter  of  common  observation ; 
and  experiments  which  I  have  conducted  on  a  small 
number  of  insects  and  birds  have  always  resulted  in 
marks  either  of  indifference  or  of  positive  distaste.  Thus 
we  see  that  both  in  their  likes  and  dislikes  a  oreat  com- 
munity  of  taste  runs  through  all  the  flower-feeding  and 
fruit-eating  animals. 

If,  now,  we  turn  to  the  carnivores  and  carrion-feeders, 
we  shall  find  a  totally  different  set  of  sympathies  and 
antipathies.  It  is  true  that  many  dogs  and  flesh-eating 
flies  love  sugar ;  but  they  also  love  numerous  other  bodies 
which  several  of  the  former  class  of  creatures  would  never 
touch.  Fresh  meat,  or  still  worse,  putrid  flesh,  does  not 
appeal  at  all  to  the  senses  of  bees  and  parrots.  Man,  of 
course,  forms  an  intermediate  link,  a  fruGjivorous  animal 
who  has  partially  adopted  carnivorous  tastes.  Hence  we 
have  a  certain  liking  for  the  flavour  of  roast  beef  and 
turkey;  some  of  us  eat  high  game  and  caviare;  and 
savages  even  prefer  meat  in  an  advanced  stage  of  decom- 


I40  THE  COLOUR-SENSE. 

position.  But  these  are  mere  surface-tastes,  while  the 
deeper-seated  ancestral  habits  come  out  strongly  in  our 
children  and  our  unsophisticated  adults.  The  liking  for 
strong-tasted  meats  and  half -putrid  preparations  has  to 
be  slowly  acquired ;  whereas  the  love  for  sugar,  for  honey, 
for  fruits,  for  all  sweet  things,  is  born  with  us  into  the 
world,  and  taken  in  with  our  first  draught  of  mother's 
milk.  And  in  this  connection  it  is  worth  while  to  note 
that  the  natural  food  of  the  human  infant  contains  62.3 
parts  of  sugar  in  1000,  while  that  of  a  herbivorous  calf 
possesses  only  45.6,^  so  that  it  becomes  necessary  in 
giving  cow's  milk  to  babies  to  sweeten  it  considerably  up 
to  the  proper  point. 

Secondly,  let  us  look  at  the  sense  of  smell.  Here  again 
we  notice  that  wherever  any  part  of  a  plant  wishes  to 
attract  animals,  it  adds  to  its  sweetness  the  extra  allure- 
ment of  perfume ;  and  the  same  perfumes  are,  as  a  rule, 
pleasant  to  all  flow^er-feeders  and  fruit-eaters  alike.  The 
delicate  odour  of  a  peach,  a  pine-apple,  or  a  strawberry 
scarcely  differs  in  kind  from  that  of  a  lily,  a  hyacinth,  or 
a  violet.  Mankind,  whose  tastes  in  this  matter  are  de- 
rived from  the  tropical  fruits,  have  equal  pleasure  with 
bees  or  butterflies  in  the  dainty  scent  of  clover  and 
meadow-sweet.  Only,  as  might  naturally  be  expected, 
the  perfumes  of  fruits  (which  we  have  already  seen  reason 
to  believe  are  comparatively  modern  structures)  are  not 
so  highly  developed  as  the  perfumes  of  flowers ;  whence 
arises  the  seeming  anomaly  that  our  olfactory  nerves  are 
more  pleasurably  stimulated  by  the  stephanotis  or  the 
jasmine,  which  is  relatively  remote  from  our  practical 
life,  than  by  the  apple  or  the  pear,  which  is  relatively 
essential.  Of  course,  the  explanation  here  is  that  the 
more  powerful  stimulant  naturally  affords  the  greater 
volume  of  pleasure,  irrespective  of  its  ulterior  useful- 
ness. 

In   this  case,   too,   we   see    the    essential    agreement 

1  Hermann,  Human  Physiology,  English  translation,  p.  121. 


COMMUNITY  OF  TASTE.  141 

between  the  higher  and  the  lower  forms  of  vegetal- 
feeders.  For  just  as  our  taste  for  sweets  corresponds  to 
the  insect's  taste  for  honey,  so  our  love  for  the  perfume  of 
flowers  is  absolutely  identical  with  the  pleasure  which 
draws  the  butterfly  towards  the  luscious  blossoms  in  our 
English  meadows.  And  it  is  w^orth  while  to  observe  that 
most  of  the  sweet-smelling  flowers  appear  to  be  quite  late 
developments  of  vegetal  life;  a  fact  which  harmonises 
well  with  the  correspondingly  late  development  of  the 
bees  and  other  highly-adapted  honey-suckers.  There  is 
no  tribe  of  plants,  for  example,  more  noticeable  for  their 
perfume  than  the  family  of  Labiates,  which  includes  the 
various  species  of  mint,  thyme,  balm,  sage,  marjoram, 
lavender,  rosemary,  horehound,  calamint,  patchouli,  hyssop, 
and  basil.  The  flowers  of  these  plants  are  almost  all 
very  peculiarly  shaped  and  highly  scented,  and  their 
attractiveness  for  bees  has  become  proverbial — the  honey 
of  poetry  is  commonly  "  redolent  of  thyme."  Now  the 
Labiates,  so  far  as  known,  are  tertiary  plants  of  rather 
late  date,  which  did  not  make  their  appearance  on  the 
earth  until  bees  and  other  specialised  honey-seekers  had 
reached  a  high  point  of  evolution.  Nor  should  we  omit 
to  notice  the  fact  that  many  of  these  plants  are  now  cul- 
tivated by  man  for  the  sake  of  this  very  property ; 
lavender  to  dry  and  use  for  scent,  patchouli  to  extract  an 
essence  for  the  handkerchief,  and  mint,  thyme,  or  sage 
to  flavour  various  preparations  for  the  table.  The  exactly 
similar  cases  of  nutmeg,  cloves,  and  other  spices,  whose 
perfume  is  famous  for  its  diffusibility,  while  the  mode  of 
their  dispersion  by  nutmeg-pigeons  has  become  classical 
in  the  pages  of  Darwin  and  Wallace,  do  not  need  further 
comment. 

In  some  few  instances  the  pleasure  of  perfume  has  been 
turned  into  a  sexual  allurement,  as  with  certain  butter- 
flies, where  the  two  sexes  exhibit  a  different  arrangement 
in  the  nervures  of  the  wings.  "In  all  cases  which  I 
know,"  says  Fritz  MuUer,  "  this  difference  in  neuration  is 


142  THE  COLOUR-SENSE. 

connected  with,  and  probably  caused  by,  the  development 
in  the  males  of  spots  of  peculiarly  formed  scales,  pencils, 
or  other  contrivances,  which  exhale  odours  agreeable  no 
doubt  to  their  females.  This  is  the  case  in  the  genera 
Mechanitis,  Dircenna,  in  some  species  of  Thecla,  &c."  ^ 
Similar  instances  occur  in  the  musk-deer  and  other  mam- 
mals, whose  perfumes  are  used  by  human  beings  as 
pleasurable  stimulants.  Indeed,  I  do  not  think  it  would 
be  too  much  to  say  that  almost  every  substance  which  we 
employ  as  a  native  scent  is  derived  either  from  a  vegetal 
product  whose  natural  function  is  the  attraction  of  ani- 
mals, or  from  an  animal  product  whose  natural  function 
is  the  attraction  of  the  opposite  sex. 

On  the  other  hand,  we  find  amongst  the  carnivores  and 
carrion-feeders  a  totally  different  form  of  olfactory  plea- 
sure. Dogs,  wolves,  and  other  predatory  mammals,  track 
their  prey  by  scent,  while  the  smell  of  raw  meat  renders 
the  larger  cats  wild  with  excitement.  Vultures  and  sopi- 
lotes  revel  in  the  hideous  smell  of  putrid  animal  matter, 
and  flies  collect  around  dung  or  decaying  meat.  Curi- 
ously enough,  too,  some  plants  have  availed  themselves 
of  this  special  taste,  and  have  laid  themselves  out,  as 
already  noticed,  to  deceive  carrion  insects  by  their  like- 
ness in  appearance  and  smell  to  putrescent  flesh.  The 
Sumatran  Rafflcsia  and  the  South  African  Hydnora  have 
large  and  lurid  blossoms,  which  thus  cunningly  induce 
flies  to  visit  them  for  the  purpose  of  laying  their  eggs,  and 
are  accordingly  fertilised  by  means  of  an  organised  de- 
ception. To  naturally  frugivorous  man,  the  scent  is,  of 
course,  simply  disgusting.  Yet  it  is  worth  notice  that  many 
savages,  who  have  acquired  for  generations  the  habit  of 
eating  half-decomposed  meat,  positively  enjoy  those  odours 
which  are  most  distasteful  to  the  nostrils  of  civilised  huma- 
nity. As  Kolben  quaintly  phrases  it,  in  his  old-fashioned 
style,  "Wliat  you  take  for  a  stink,  a  Hottentot,  if  you 

^  In  "Nature,"  November  29,  1877. 


COMMUNITY  OF  TASTE.  143 

will  believe  him,  receives  as  the  most  agreeable  per- 
fume." 1 

Hence  one  may  see  how  futile  is  the  argument  of 
Geii:^er,  who  remarks,  as  illustratinGr  the  sensuous  in- 
feriority  of  the  lower  animals,  that  it  would  be  -useless  to 
offer  a  dog  a  bouquet  to  sniff  at.^  Of  course  the  dog  has 
no  reason  for  being  pleased  with  a  perfume  which  has 
no  special  relation  to  himself  or  his  ancestors  in  any  way ; 
but  if  we  offer  him  a  piece  of  meat,  or  set  him  to  hunt 
down  game,  we  shall  find  how  keenly  he  has  been  pro- 
vided by  nature  with  senses  to  aid  him  in  his  ow^n  mode 
of  life.  In  fact,  we  can  only  expect  pleasure  to  be  felt 
where  ancestral  habit  has  produced  a  corresponding 
sensory  system.  The  transference  of  feeling  whereby  we 
are  enabled  to  enjoy  the  perfume  of  flowers  does  not  con- 
tradict this  general  principle,  for  it  is  really  analogous  to 
the  transference  whereby  the  humming-bird  sipped  the 
syrup  which  resembled  the  native  nectar,  or  whereby  we 
ourselves  enjoy  sweetmeats  and  cakes  through  our  here- 
ditary liking  for  fruits  and  berries.  Honey  is  a  more 
concentrated  form  of  sugar  than  that  which  we  get  in 
strawberries  or  oranges,  and  frangipanni  is  a  more  con- 
centrated form  of  perfume  than  that  which  we  get  in 
peaches  and  pine-apples ;  but  they  probably  act  in  just 
the  same  way,  though  to  a  greater  extent,  upon  the  nerves 
involved  as  do  the  original  stimulants,  and  consequently 
they  need  no  special  explanation.  Very  different,  how- 
ever, would  be  the  case  if  a  dog  or  any  other  animal  were 
to  feel  pleasure  in  a  stimulation  derived  from  some  object 
which  had  no  kind  of  relation  to  his  ancestral  habits. 
Such  an  instance,  one  might  venture  to  say,  would  be 
wholly  inexplicable,  and  opposed  to  all  the  known  prin- 
ciples of  scientific  psychology. 

The  sense  of  hearing,  though  interesting  in  itself  through 

1  Kolben,  "Cape  of  Good  Hope,"  2  ''Zur  Entwickelungsgeschichte 
vol.  i.  p.  231.  der  Menschheit,  iii.  p.  50. 


144  THE  COLOUR-SENSE. 

its  connection  with  song-birds  and  the  sexual  allurements 
of  sound  amongst  sundry  insects,  has  so  little  relation 
with  our  present  subject,  that  I  must  reluctantly  pass  it 
over  here. 

Lastly,  then,  we  arrive  at  the  sense  of  siglit,  which  we 
must  only  examine  with  special  reference  to  the  taste  for 
colour.  And  here,  as  before,  we  note  at  once  that  those 
portions  of  plants  which  lay  themselves  out  to  attract 
animals  are  almost  without  exception  conspicuous  for 
their  bright  colours.  Entomophilous  flowers,  as  we  have 
already  abundantly  observed,  have  a  monopoly  of  brilliant 
corollas,  while  fruits  -  proper  differ  from  nuts  in  the 
startling  vividness  of  their  hues.  These  facts  would  go  by 
themselves  to  prove  that  flower-feeding  and  fruit-eating 
animals  find  an  allurement  in  colour.  It  is  certainly 
a  noticeable  fact  that  just  as  the  sweetness  of  fruits 
answers  to  the  sweetness  of  honey,  and  just  as  the  scent 
of  fruits  answers  to  the  scent  of  flowers,  so  do  the  colours 
of  fruits  answer  exactly  to  the  colours  of  flowers.  It  would 
seem  as  though,  in  every  case,  nature  found  a  single  mode 
of  modifying  the  nervous  substance  was  amply  sufficient 
(because  simplest  and  easiest)  alike  for  insect  and  reptile, 
for  bird  and  ape  and  human  being. 

Some  special  facts  help  to  point  in  the  same  direction. 
Thus  we  find  within  the  limits  of  a  single  family,  the 
Eosacese,  a  large  number  of  fruits -proper,  the  plum,  the 
apple,  the  hip,  the  haw,  the  strawberry,  the  raspberry,  and 
the  bramble,  in  which  the  pericarp  or  other  succulent 
portion,  besides  being  sweet  and  scented,  is  more  or  less 
brilliantly  coloured ;  and  again,  we  also  find  an  aberrant 
member,  the  almond,  whose  seed  is  enclosed  in  a  nut,  and 
whose  pericarp  accordingly  is  hard,  dry,  and  green  or 
brownish,  after  the  usual  fashion  of  nuts.  Or  once  more, 
we  know  that  in  most  Oceanic  islands  there  are  few  flying 
insects,  and  that  most  of  the  flowers  are  destitute  of  bright 
corollas ;  but  Mr.  Wallace  has  pointed  out  that  in  a  few, 
cases,  where  honey-sucking  birds  frequent  such  islands 


COMMUNITY  OF  TASTE.  145 

the  flowers  are  extremely  large  and  handsome.^  This  fact 
clearly  shows  that  the  birds  in  question  find  colour  quite 
as  attractive  as  do  bees  or  butterflies. 

I  do  not  propose  to  enter  very  fully  into  this  question 
until  w^e  have  seen  w^hat  light  may  be  cast  upon  it  by  the 
examples  collected  and  the  inferences  drawn  in  the  suc- 
ceeding chapter.  But  I  should  like  to  point  out  here 
that  if  our  general  theory  of  pleasure  be  well-founded, 
it  must  necessarily  result  that  flower-feeding  and  fruit- 
eating  animals  should  derive  agreeable  sensations  from 
coloured  objects.  So  soon  as  the  eyes  of  insects  or  birds 
have  become  sufficiently  differentiated  to  discriminate  the 
pinkish  or  ruddy  flower-cases  and  fruit-vessels  from  the 
green  leaves  around  them,  and  to  employ  their  nascent 
sense  in  the  quest  for  food,  so  soon  must  the  special 
nerves  exercised  and  strengthened  in  this  process  receive 
some  faint  pleasure  from  their  due  stimulation.  And 
the  more  developed  the  nerves  become,  the  more  intense 
must  be  the  resulting  enjoyment,  till  at  last  an  ever-in- 
creasing gratification  would  grow  up  side  by  side  with  the 
growth  of  entomophilous  blossoms  and  coloured  fruit,  be- 
coming stronger  and  stronger  day  by  day  as  the  structures 
increased  by  practice  in  calibre  and  power. 

Two  short  passages  from  the  works  of  two  leading 
evolutionists  will  serve  to  bring  out  in  strong  relief  the 
position  here  assumed.  Mr.  A.  E.  Wallace  thus  sums  up 
his  view  with  regard  to  the  nature  of  colour-perception 
in  the  lower  animals  : — "  The  fact  that  the  higher  verte- 
brates, and  even  some  insects,  distinguish  what  are  to 
us  diversities  of  colour,  by  no  means  proves  that  their 
sensations  of  colour  bear  any  resemblance  whatever  to 
ours.  An  insect's  capacity  to  distinguish  red  from  blue 
or  yellow  may  be  (and  probably  is)  due  to  perceptions  of 
a  totally  distinct  nature,  and  quite  unaccompanied  by  any 
of  that  sense  of  enjoyment  or  even  of  radical  distinctness 
which  pure  colours  excite  in  us.     Mammalia  and  birds, 

1  Tropical  Nature,  p.  238. 


146  THE  COLOUR-SENSE. 

whose  structure  and  emotions  are  so  similar  to  our  own, 
do  probably  receive  somewhat  similar  impressions  of 
colour ;  but  we  have  no  evidence  to  show  that  they  ex- 
perience pleasurable  emotions  from  colour  itself,  when 
not  associated  with  the  satisfaction  of  their  wants  or  the 
gratification  of  their  passions."  ^  From  the  whole  of  this 
passage,  with  all  due  deference  to  ]\Ir.  AVallace  (for  most 
of  whose  work  I  entertain  the  deepest  respect),  I  must 
take  leave  to  differ  toto  codo.  Each  of  its  three  sentences 
appears  to  me  to  contain  a  fallacious  position.  For  the 
first,  the  burden  of  proof  lies  distinctly  with  Mr.  Wallace, 
not  with  his  opponents;  because,  where  the  external 
stimulus  is  the  same,  and  where  a  general  continuity  of 
structure  exists,  we  are  not  justified  in  assuming  a  dif- 
ference of  sensation  without  some  special  reason;  nor  do 
I  believe  that  so  clear  a  thinker  as  the  author  of  the 
*'  Malay  Archipelago  "  would  have  assumed  such  a  differ- 
ence, were  it  not  for  that  predisposition  to  find  some 
eff'ective  distinction  between  man  and  the  lower  animals 
which  has  so  often  led  him  into  questionable  conclusions. 
For  the  second,  it  seems  to  me  that,  since  the  insect's  need 
for  discriminating  colour  is  far  greater  than  our  own, 
analogy  would  lead  us  to  suppose  that  his  enjoyment 
would  be  even  deeper,  and  his  sense  of  distinctness  more 
marked,  than  in  the  human  subject.  For  the  third,  the 
single  instance  of  the  oft-quoted  bower-birds,  who  collect 
coloured  objects  to  decorate  their  meeting  places,  shows 
that  some  vertebrates  at  least  possess  a  liking  for  brilliant 
hues  in  themselves,  of  a  truly  aesthetic  sort :  and  the  be- 
haviour of  monkeys  with  regard  to  flowers  and  birds,  or 
to  red  shawls  and  other  strikingly-dyed  articles,  would 
seem  to  point  in  the  same  direction.  For  the  rest,  Mr. 
Darwin  has  gathered  together  a  few  isolated  instances  of 
disinterested  love  for  colour  in  a  well-known  section  of 
his  "  Descent  of  Man."  ^  It  is  true  that  the  evidence  on 
this  head  is  still  far  from  satisfactory;  but  it   must   be 

^  Tropical  Nature,  p.  243.  2  Yo\.  ii.  p.  no. 


COMMUNITY  OF  TASTE.  147 

remembered  tliat  without  the  assistance  of  language  de- 
finite information  as  to  tastes  cannot  be  procured  except 
with  great  difficulty,  and  that  human  infants  only  dis- 
play the  love  for  colour  in  the  same  simple  ways  as  mon- 
keys or  bower-birds. 

The  second  passage  to  which  I  would  refer  is  one  from 
our  great  naturahst  himself.  "  How  the  sense  of  beauty  in 
its  simplest  form,"  says  Mr.  Darwin, — "  that  is,  the  recep- 
tion of  a  peculiar  kind  of  pleasure  from  certain  colours, 
forms,  and  sounds, — was  first  developed  in  the  mind  of 
man  and  of  the  lower  animals,  is  a  very  obscure  subject. 
The  same  sort  of  difficulty  is  presented  if  we  inquire  how 
it  is  that  certain  flavours  and  odours  give  pleasure,  and 
others  displeasure.  Habit  in  all  these  cases  appears  to 
have  come  to  a  certain  extent  into  play ;  but  there  must 
be  some  fundamental  cause  in  the  constitution  of  the  ner- 
vous system  in  each  species."^  Now  this  fundamental 
cause  I  believe  to  reside  in  the  general  law  that  pleasure 
accompanies  normal  stimulation  when  not  excessive  in 
amount;  while  the  influence  of  ancestral  habit,  joined 
with  natural  selection,  has  so  modified  the  nervous  system 
in  each  case  that  it  finds  itself  normally  stimulated  by 
those  external  agents  whicli  conduce  to  the  general  wel- 
fare of  the  organism,  and  excessively  or  destructively 
stimulated  by  those  which  conduce  to  its  general  detri- 
ment.2  Accordingly,  I  infer  that  in  all  fruit-eating  and 
flower-feeding  species,  a  taste  for  sweet  flavours,  delicate 
perfumes,  and  bright  colours  will  have  been  slowly  deve- 
loped by  the  hereditary  mode  of  life ;  and  that  the  taste 
so  developed  will  have  opportunities  for  exerting  itself  in 
the  sexual  selection  of  bright-coloured  mates. 

If  this  be  so,  then  it  must  follow  that  flower-feeding 
and  fruit-eating  insects  or  vertebrates  will  be  specially 
distinguished  from  other  animals  by  the  exceptional  bril- 
liancy of  their  colouration.     In  the  next  chapter  we  will 

1  Origin  of  species,  6th  edit.,  p.  162.     tics,"  pas«u7i,  where  this  main  prin- 

2  See  my    "Physiological   Ji^sthe-    cii)le  is  worked  out  in  detail. 


148  THE  COLOUR-SENSE, 

submit  our  general  conclusion  to  the  test  tliTis  suggested  to 
us,  and  if  we  find  that  bright  hues  are,  as  a  matter  of  fact, 
unusually  common  amongst  those  species  in  which  we  have 
inferred  a  'priori  that  a  taste  for  brilliancy  would  have 
been  evolved  by  the  circumstances  of  their  life,  then  we 
shall  have  added  another  item  to  our  cumulative  proof 
of  the  existence  and  influence  of  a  colour-sense  among 
the  lower  animals.  Just  as  we  saw  that  the  taste  for 
sweets,  formed  upon  flowers  and  fruits,  could  be  trans- 
ferred to  syrup,  sugar,  honey,  bonbons,  cakes,  and  pud- 
dings ;  just  as  we  saw  that  the  human  liking  for  dainty 
perfumes,  formed  upon  strawberries  and  oranges,  could  be 
transferred  to  hyacinths  and  heliotropes :  so,  I  believe, 
the  love  for  colour,  formed  upon  the  natural  food  of  the 
various  species,  can  be  transferred  to  the  choice  of  beauti- 
ful mates,  and,  strengthened  by  this  transference,  can  be 
handed  down  by  heredity  to  mankind  till  it  results  at  last 
in  the  disinterested  delight  in  the  sunset  and  the  autumn 
hues,  in  the  flowers  of  our  gardens,  the  varying  tints  of 
our  landscapes,  and  the  exquisite  harmony  of  our  Guides 
and  our  Eossettis.  Let  us  see,  then,  how  far  the  facts  of 
nature  will  bear  out  the  theory  on  this  subject  which  we 
have  framed  from  the  analogy  of  our  other  senses. 


(     149     ) 


CHAPTER  IX. 

THE  DIRECT  REACTION  OF   THE   COLOUR-SENSE   UPON 
THE   ANIMAL   INTEGUMENTS. 

If  any  unscientific  person  were  asked  to  name  tlie  two  most 
beautiful  classes  of  animals  in  the  world,  he  would  unhe- 
sitatingly answer,  ''  Butterflies  and  humming-birds."  It 
is  a  significant  fact  that  these  are  perhaps  the  most  exclu- 
sively flower-haunting  of  all  invertebrate  or  vertebrate 
creatures  respectively.  And  if  he  were  asked  to  name  any 
other  birds,  besides  the  single  family  above  mentioned, 
which  are  specially  conspicuous  for  their  brilliant  colour- 
ation, he  would  probably  reply,  ''  Parrots  and  their  allies." 
It  is  an  equally  significant  fact  that  these  birds  are  fruit- 
eaters.  Following  up  the  hint  thus  given  us,  we  may  run 
through  the  chief  instances  of  brilliant  species  in  both 
great  divisions  of  articulates  and  vertebrates,  in  order  to 
discover  whether  there  is  any  constancy  of  connection 
between  the  nature  of  the  food  and  the  colouration. 

As  before,  we  may  narrow  down  our  consideration  of  the 
articulates  to  the  great  group  of  insects,  because  we  know 
too  little  about  the  habits  of  their  marine  congeners  to 
argue  with  any  certainty  as  to  their  traits ;  while  the  other 
land-articulates  are  relatively  unimportant  for  our  present 
purpose.  Now  amongst  the  insects,  the  most  brilliant 
order  are  the  Lepidoptera,  including  both  the  butterflies 
and  moths,  which,  it  need  hardly  be  said,  feed  upon  flowers. 
Of  course,  it  may  be  readily  objected  that  the  amount  of 
food  eaten  by  the  perfect  winged  insects  is  relatively  small, 
and  that  the  caterpillars  live  for  the  most  part  upon  the 


I50  THE  COLOUR-SENSE. 

green  portions  of  plants.  Indeed,  some  butterflies  possess 
no  mouths  at  all,  and  pass  the  whole  of  their  short  lives 
by  the  expenditure  of  energy  laid  up  in  the  larval  condi- 
tion. Yet  this  objection  does  not  really  invalidate  the 
general  conclusion ;  for  the  eyes  of  the  perfect  insects  have 
been  evidently  adapted  to  the  colours  of  flowers,  and  the 
main  object  of  their  winged  state  is  the  perpetuation  of 
the  species ;  so  that  we  can  easily  understand  how  the 
tastes  ancestrally  formed  in  their  last  stage  should  domi- 
nate the  selection  of  their  mates.  Hence  we  find  that  the 
colours  of  caterpillars  are  mostly  protective,  being  due  to 
natural -selection  alone,  while  those  of  butterflies  are  mostly 
attractive,  being  largely  due  to  sexual  selection. 

Furthermore,  if  we  examine  the  Lepidoptera  in  detail,  we 
shall  find  similar  conclusions  thrust  upon  us.  They  may 
be  divided  into  two  great  sections, — the  moths  and  the 
butterflies, — of  which  the  former  are  mainly  nocturnal  or 
crepuscular,  while  the  latter  are  mainly  diurnal.  Now 
there  can  be  no  comparison  as  to  brilliancy  between  the  vast 
majority  of  these  two  groups.  The  moths  vary  for  the 
most  part  from  dingy  grey  to  dusky  black,  while  the  but- 
terflies revel  in  every  shade  of  golden  yellow,  splendid 
crimson,  and  metallic  blue.  Again,  the  eyes  of  these  two 
divisions  differ  in  structure  in  a  manner  which  suggests 
the  inference  that  the  diurnal  insects  are  much  better  pro- 
vided with  optical  discrimination  than  their  nocturnal 
allies,^  especially  when  the  facts  are  compared  with  cer- 
tain exactly  similar  or  corresponding  peculiarities  in  the 
nerve-terminals  in  the  eyes  of  owls  and  bats.^ 

Nor  does  the  argument  stop  here.  Certain  species  or 
families  of  moths  fly  by  day,  and  these  [e.g.,  the  crimson- 
speckled  Deiopeia  pulcliella,  Callimorplia  dominula,  the 
Agaristidce,  ^gcriidm,  Zygmnidm,  &c.)  are  as  brightly  tinted 
as  any  butterflies.    Mr.  Bates  mentions  a  Brazilian  Urania, 

^  See  a  paper  by  Mr.  B.  T.  Lowne,  F.L.S.,  in  Proc.  Roy.  Soc,  No.  clxxxvi. 
p.  26  r,  1878. 
^  See  below. 


DIRECT  RE  A  CTION.  x  5 1 

"  a  beautiful  tailed  and  gilded  moth,  whose  habits  are  those 
of  a  butterfly ;  "  ^  and  I  know  by  personal  experience  the 
Jamaican  species  of  similar  tastes,  whose  wings  are  exqui- 
sitely dappled  with  black,  green,  and  gold.  Indeed,  it 
may  be  stated  generally  that  most  brilliant  insects  are 
fond  of  displaying  themselves  in  the  open  sunlight ;  while 
conversely  most  insects  which  frequent  dark  places  or  fly 
by  night  alone  are  dusky  and  ugly.  By  the  side  of  these 
facts  it  is  well  to  remember  that  diurnal  flowers,  which 
appeal  to  bees  and  butterflies,  have  corollas  in  every 
variety  of  red,  blue,  orange,  and  purple ;  while  nocturnal 
flowers,  which  appeal  to  moths,  are  generally  white  or 
pale  yellow  in  hue. 

If  we  compare  the  carrion-feeding  and  omnivorous  flies 
with  the  flower-haunting  Lepidoptera,  we  see  at  once  the 
difference  of  taste,  as  exhibited  in  the  presence  or  absence 
of  sexual  selection.  The  flies  are  generally  dark  and 
inconspicuous,  with  thin  transparent  wings;  and  what- 
ever beauty  they  possess  is  due  to  mere  surface-play  of 
interference-colours,  not  to  the  existence  of  distinct  pig- 
ments. Nothing  in  the  nature  or  appearance  of  their 
ordinary  food-stuffs  would  lead  us  to  credit  them  with  any 
ancestral  love  for  pure  and  beautiful  hues. 

There  are,  however,  some  striking  exceptions  amongst 
the  dipterous  insects,  which  fully  bear  out  our  general 
conclusion.  The  tribe  of  Brachystomatidce  are  "  large  flies, 
adorned  with  brilliant  colours,  which  for  the  most  part 
haunt  flowers,  living  upon  honey."  ^  The  Xotacanthte 
"  are  also  frequently  brilliantly  coloured.  They  generally 
frequent  flowers."  The  Conopidse,  too,  "  are  elegantly 
variegated  in  their  colours.  They  may  be  found  in  great 
abundance  during  the  summer,  hovering  upon  their  power- 
ful wings  over  flowers  in  gardens  and  elsewhere."  The 
invariability  of  this  conjunction  will  hardly  allow  us  to 
recrard  it  as  accidental. 

o 

1  The  Naturalist  on  the  Amazons,  ^  Dallas,  The  Animal  Kin^dum, 
p.  105.  p.  191. 


152  THE  COLOUR-SENSE. 

Beetles  or  Coleoptera  show  us  like  results.  The  car- 
rion-feeders are  for  the  most  part  black  and  unattractive, 
as  are  also  the  nocturnal  species  and  those  which  live  in 
water.  But  the  brilliant  species  are  often  flower-feeders, 
and  fly  much  in  the  sunlight,  exhibiting  their  exquisite 
metallic  sheen,  and  displaying  their  beauty  to  their 
mates.  If  we  take  the  Lamellicorn  beetles  in  particular, 
we  shall  find  a  very  instructive  difference  between  two 
of  their  closely-allied  families.  The  cockchafers  feed  on 
leaves,  and  they  are  some  of  the  dingiest  creatures  of  their 
class  ;  but  the  Cetoiiiadcc  feed  upon  flowers,  as  their  English 
name  of  "  rose-beetles  "  implies,  and  they  are  conspicuous 
for  the  beauty  of  their  colouring,  including  "  a  vast  num- 
ber of  the  most  brilliant  exotic  species."  "  It  is  a  signifi- 
cant fact,  too,  that  their  mandibles  have  been  specially 
modified,  so  as  to  enable  them  to  lick  up  honey,  which 
clearly  shows  a  long  persistence  in  flower-haunting  habits, 
quite  sufi&cient  to  account  for  the  formation  of  a  definite 
taste  for  colour.  "  Those  species,"  says  Latreille,  speak- 
ing of  Lamellicorns  generally,  "  which  live  in  the  perfect 
state  upon  vegetable  substances,  are  remarkable  for  the 
brilliancy  of  the  metallic  colours  with  which  they  are 
adorned.  But  the  majority  of  the  other  species,  which 
subsist  on  decomposing  vegetation,  manure,  tan,  or  excre- 
mentitious  matter,  are  generally  of  a  uniform  black  or 
brown  hue."  The  magnificent  Buprestidse  are  also,  in  many 
cases  at  least,  flower-haunters.  The  tetramerous  beetles, 
including  the  gorgeous  Longicorns,  may  be  regarded  as 
mainly  flower-feeding  or  plant-haunting  insects,  and  their 
colours,  as  a  rule,  are  very  brilliant.  Similarly,  among 
heteromerous  beetles,  the  Trachelia  of  Professor  West- 
wood  are  active  diurnal  animals,  most  of  which  live  upon 
the  leaves  or  suck  the  honey  of  flowers,  and  they  are 
often  adorned  with  beautiful  colours ;  but  the  Atrachelia, 
nocturnal  in  their  habits  and  foul  feeders,  are  generally 
black  and  dingy  in  hue.  Altogether,  though  it  would  be 
difficult  to  sum  up  so  very  varied  a  group  as  the  Coleop- 


DIRECT  RE  A  CTION.  153 

tera  in  a  single  sentence,  I  think  a  careful  examination 
will  convince  the  inquirer  that  here,  too,  a  general  con- 
nection exists  between  brilliancy  of  hue  and  flower-feed- 
ing or  fruit-eating  habits. 

When  we  turn  to  the  Hymenoptera,  or  bee  and  wasp 
tribe,  a  great  difficulty  at  first  sight  arises  in  our  way.  It 
would  seem  as  though  some  of  these  insects  ought  to  be 
of  all  others  the  most  gorgeously  arrayed,  and  yet  for  the 
most  part  they  are  but  plain  and  inconspicuous  creatures. 
However,  a  closer  view  dispels  the  doubt.  Only  one  tribe 
of  the  Hymenoptera,  that  of  the  Anthophila,  or  bees,  is 
specially  adapted  for  feeding  on  flowers.  Now  these  fall 
into  two  classes,  the  social  and  the  solitary ;  and  the  habits 
of  the  former  class,  of  course,  place  them  almost  entirely 
outside  the  sphere  of  sexual  selection.  The  queen  or 
mother-bee,  a  prisoner  for  life,  does  not  herself  seek  honey 
among  flowers,  and  those  bees  which  do  so  have  no  power 
of  transmitting  their  tastes  or  habits  to  descendants. 
Indeed,  the  whole  question  of  heredity  in  these  interest- 
ing animals  remains  involved  in  so  much  mystery,  that  it 
would  be  useless  to  base  any  arguments  upon  it  in  either 
direction. 

On  the  other  hand,  the  solitary  bees  are  often  beauti- 
fully coloured,  as  in  the  well-known  case  of  the  carpenter- 
bee.  The  Nomadae,  or  cuckoo-bees,  are  also  very  brilliant 
insects.  The  omnivorous  wasps  do  not  exhibit  equal 
beauty ;  and  the  almost  wingless,  highly  social,  and  mainly 
carnivorous  ants  are  quite  inconspicuous  animals,  pro- 
bably possessing  colour-perception  in  a  very  sight  degree. 
But  the  Chrysidse,  a  family  of  lower  Hymenoptera,  are 
also  solitary  flower-haunters,  and  "  in  the  richness  of  their 
colours  they  vie  with  humming-birds." 

Of  course,  it  cannot  be  denied  that  a  few  less  notable 
classes  of  insects  which  do  not  haunt  flowers  are  never- 
theless more  or  less  brilliant  in  their  colouring.  But  this 
does  not  interfere  with  the  general  truth  of  our  inference 
that  flower-feeders  are  specially  noticeable  for  their  bright 


154  THE  COLOUR-SENSE. 

lilies.  If  we  can  find  ground  for  believing  that  those  spe- 
cies which  habitually  seek  their  food  in  gay  blossoms  have 
developed  a  peculiar  love  for  colour,  which  is  shown  in 
their  choice  of  mates,  we  shall  have  done  quite  as  much  as 
is  needful.  Besides,  other  sources  exist  from  which  a  love 
for  colour  may  be  derived  as  well  as  from  flowers.  For 
example,  the  Orthopterous  family  of  Mantidse,  or  praying- 
insects,  are  noticeable  in  many  instances  for  their  bright 
tints ;  but  as  they  live  by  devouring  other  insects,  a  taste 
of  the  sort  may  have  been  generated  indirectly  in  their 
case  from  the  nature  of  their  food.  Still,  most  of  the 
Mantidse  seem  rather  to  be  deceptively  coloured  like  their 
surroundings,  so  as  to  escape  the  notice  both  of  their  prey 
and  of  their  enemies  among  birds.  A  similar  explanation 
must  be  given  in  the  case  of  the  Phasmidae,  or  leaf  and 
stick  insects,  whose  colouring,  though  sometimes  compara- 
tively striking  when  seen  in  a  cabinet,  is  purely  imitative 
of  the  foliage  or  fallen  sticks  around  them.  Many  flower- 
haunting  spiders,  too  (to  travel  for  a  moment  outside  the 
limits  of  the  true  insects),  are  "  exquisite  gems  "  of  ruby 
or  sapphire  colouration ;  yet  we  must  rather  attribute  their 
magnificent  hues  to  the  need  for  imitating  the  petals  on 
which  they  creep  than  to  sexual  selection.  Such  instances, 
however,  in  no  way  militate  against  our  main  conclusion ; 
they  only  show  that  other  causes  at  work  have  sometimes 
produced  similar  results  to  those  which  we  are  contem- 
plating, though  in  a  different  manner.  Thus  it  is  quite 
possible  that  the  beauty  of  the  tiger-beetles  may  be  due 
to  their  habit  of  huntincf  other  brio^ht- coloured  insects  in 
the  open  sunlight. 

There  still  remains  a  margin  of  inexplicable  cases, 
as  might  naturally  be  expected,  for  the  study  of  these 
questions  is  yet  in  its  infancy,  and  only  a  few  isolated 
endeavours  have  hitherto  been  made  to  account  at  all  for 
the  external  appearance  of  animals.  Among  such  may 
be  mentioned  the  gorgeous  tropical  locusts,  the  dragon- 
flies  (which,  however,  prey  upon  many  brilliant  species), 


DIRECT  RE  A  CTION.  155 

and  several  of  the  Longicorn  beetles.  But  all  these  in- 
stances cannot  blind  us  to  the  fact  that  if  we  look  at  the 
flower-haunting  insects  in  the  mass  they  are  by  far  the 
most  conspicuous  for  beauty  of  their  kind.  It  is  not 
necessary  to  explain  in  detail  the  colouring  of  every  in- 
dividual species — an  endless  task,  which  would  demand 
far  more  competent  treatment  than  I  could  give :  it  is 
quite  sufficient  if  we  find  a  general  coincidence  between 
bright  food  and  bright  hues  in  the  feeder,  without 
pretending  at  once  to  account  for  every  apparent  ex- 
ception. 

And  now,  before  we  pass  on  to  examine  the  vertebrate 
world  in  the  same  manner  as  we  have  here  examined  the 
articulate,  we  must  pause  a  moment  to  meet,  or  rather 
to  touch  lightly,  a  powerful  objection  which  has  been 
urged  against  the  whole  theory  of  sexual  selection  by  no 
less  a  writer  than  Mr.  A.  E.  Wallace.  In  his  work  on 
"  Tropical  Nature,"  that  ingenious  evolutionist  endeavours 
entirely  to  overthrow  Mr.  Darwin's  laborious  superstruc- 
ture, raised  with  so  much  toil  and  skill  in  the  "  Descent  of 
Man,"  and  to  substitute  for  the  doctrine  of  A'oluntary 
choice,  which  the  older  naturalist  there  advanced,  a  number 
of  minor  principles,  whose  joint  action  may  be  supposed 
to  have  produced  the  existing  colours  of  the  animal  world. 
Mr.  Wallace  has  urged  his  objections  with  even  more 
than  his  usual  ingenuity  ;  and  I  may  frankly  confess  that 
he  has  attacked  the  theory  of  sexual  selection  with  such 
judicious  vigour  that  I  felt  inclined  on  first  reading  his 
essays  to  abandon  entirely  all  that  part  of  the  present 
work  which  was  based  on  the  orio-inal  doctrine  enunciated 
by  Mr.  Darwin.  On  fuller  consideration,  however,  I  have 
determined,  though  with  much  hesitation,  to  retain  it,  in 
hopes  that  the  few  suggestions  which  I  have  to  make 
upon  the  question  may  possibly  contribute  to  a  clearer 
comprehension  of  its  issues,  and  to  its  ultimate  settle- 
ment in  one  direction  or  the  other.  I  cannot  for  a 
moment  pretend  to  meet  a  distinguished  specialist  like 


156  THE  COLOUR-SENSE. 

Mr.  "Wallace  on  liis  own  ground ;  nor  do  I  wish  to  dis- 
pute the  force  and  accuracy  of  many  among  his  criticisms ; 
yet  I  trust  I  may  be  able  to  add  my  small  quotum  of  facts 
and  inferences  to  the  whole  data  for  a  final  opinion,  and 
I  believe  that  the  very  generalisation  which  it  is  the 
object  of  the  present  chapter  roughly  to  establish,  may  be 
useful  in  showing  some  additional  basis  for  the  theory  of 
sexual  selection.  For  if  we  find  that  ^fruit-eating  and 
flower-feeding  animals  do  really  exhibit  unusually  beauti- 
ful colours,  then  we  shall  have  some  further  ground  for 
believing  that  they  do  exert  some  vague  sort  of  choice  or 
preference  in  the  search  for  mates. 

Accordingly,  I  shall  jot  down  in  passing,  under  each 
head,  such  points  as  occur  in  relation  to  this  vexed  ques- 
tion. 

In  the  first  place,  it  is  well  to  remember  that  sexual 
selection  does  not  necessarily  imply  a  deliberate  exercise 
of  will,  or  comparison  between  the  rival  charms  of  various 
possible  mates,  which  seems  hardly  probable  in  the  case 
of  insects  at  least.     We  must  guard  against  the  error  of 
transferring  our  own  highly-developed  notions  of  beauty 
to  the  simple  half- conscious  minds  of  beetles  or  butter- 
flies.   With  us,  beauty  is  a  very  complex  idea,  compounded 
of  numerous  presentative,  representative,  and  re-represen- 
tative elements ;  and  our  choice  of  mates  is  a  conscious 
selection,  guided  more  or  less  deliberately  by  many  com- 
plicated considerations,  often  too  numerous  for  analysis 
even  in  our  own  minds.     But,  without  attributing  to  the 
butterfly  any  such  highly-evolved  feelings,  w^e  may  well 
believe  that  certain  individuals,  whose  brilliant  colours 
contrasted  strikingly  with  the  green  foliage  about  them, 
might  more  readily  succeed  in  attracting  the  attention  of 
mates  than  their  dingier  compeers.    We  know  that  the  eyes 
of  insects  are  allured  by  the  colours  of  flowers,  which  have 
been  developed  for  this  very  purpose :  and  there  is  there- 
fore nothing  improbable  in  the  supposition  that  they  are 
also  allured  by  bright  hues  in  their  fellows.     In  short,  I  am 


DIRECT  RE  A  CTION.  1 57 

inclined  to  suggest  that  conspicuousncss  rather  than  leauty 
in  our  human  sense  is  aimed  at  by  the  butterfly's  wing. 
To  some  this  will  doubtless  appear  equivalent  to  a  sur- 
render of  the  whole  position ;  but  a  little  reflection  will 
probably  remove  such  an  apprehension.  For  the  sense  of 
beauty  in  its  simplest  form,  as  Mr.  Darwin  rightly  puts  it, 
is  nothing  more  than  "  the  reception  of  a  peculiar  kind  of 
pleasure  from  certain  colours,  forms,  and  sounds."  ^  Now 
we  have  seen  reason  to  believe  that  the  insect  feels  some 
slight  pleasure  in  the  perception  of  colour  in  flowers ;  and 
we  may  also  conclude  that  the  pleasure  is  equally  felt 
from  the  similar  stimulation  of  a  brilliant  mate.  In  either 
case,  it  seems  probable  that  a  semi-automatic  action  is  set 
up  by  the  sight  of  the  bright  hue,  which  leads  on  the  insect 
instinctively  to  the  blossom  or  the  opposite  sex  alike. 
Such  a  selective  process  does  not  seem  to  me  at  all  to 
transcend  the  narrow  faculties  of  a  beetle  or  a  butterfly. 
Mates  on  this  theory  are  not  chosen  on  account  of  their 
brilliancy,  but  their  brilliancy  renders  them  the  most 
natural  objects  to  choose. 

The  familiar  instance  of  the  moth  and  the  candle  shows 
us  this  automatic  tendency  in  its  fullest  form.  In  that  case 
it  w^ould  seem  as  though  the  intensity  of  the  visual  stim- 
ulus set  up  a  motor  activity  of  the  wings,  which  w^ould 
become  more  and  more  powerful  the  more  directly  the  eyes 
of  the  insect  were  turned  towards  the  light.  Accordingly, 
any  random  movements  in  that  direction  would  be  fol- 
lowed by  more  and  more  rapid  gyrations,  ending,  as  we 
know,  in  the  central  flame,  whenever  the  eyes  both  pointed 
straight  toward  that  quarter.  We  must  conclude  here  that 
in  the  natural  circumstances  of  moths  few  bright  objects 
would  occur  around  them,  except  flowers,  and  so  the  eye 
has  probably  been  connected  with  the  motor  system  in 
such  a  manner  that  the  reception  of  a  light- stimulus  acts 
immediately  upon  the  wings.  In  the  presence  of  such  a 
rare  and  unpremeditated  object  as  a  candle,  the  hereditary 

^  Origin  of  SiJecies,  sixth  edition,  p.  162. 


158  THE  COLOUR-SENSE. 

instinct  or  organised  habit  becomes  a  bad  guide,  finds  itself 
at  fault,  and  finally  results  in  the  insect's  death.  But  the 
case  is  very  much  like  that  of  a  human  child,  who  knowing 
that  bright  red  berries  are  usually  sweet  and  innocuous, 
poisons  itself  with  those  of  the  cuckoo-pint  or  the  yam. 
The  instinctive  pleasure  can  only  have  been  adapted  to  the 
usual  environment  of  the  race,  not  to  special  and  excep- 
tional circumstances  like  artificial  lights  and  poisonous 
berries. 

It  is  possible  that  the  light  of  fire-flies  and  glow-worms 
may  be  similarly  of  use  for  the  guidance  of  the  sexes, 
though  Mr.  Belt  believes  it  to  be  a  warning  mark  of  inedi- 
bility. However  this  may  be,  it  is  certain  that  butterflies 
and  insects  generally  are  so  constituted  that  they  can  dis- 
tinguish  their  own  mates  unerringly  from  all  others,  even 
though  the  difference  between  the  species  be  almost 
microscopical.  Whether  this  discrimination  be  due  to 
sight,  or,  as  some  authors  maintain,  to  smell,  it  shows 
equally  that  a  minute  correspondence  exists  between  the 
senses  of  the  insect  and  its  habits  of  life.  And  as  this 
correspondence,  so  far  as  each  separate  species  is  con- 
cerned, must  have  had  a  beginning  at  some  time  or  other, 
and  consequently  a  cause,  there  seems  no  sufficient  ground 
for  doubting  that  conspicuousness  of  colour  formed  one  of 
the  determining  conditions.  Indeed,  I  cannot  myself  see 
why  Mr.  Wallace,  who  allows  the  attractive  nature  of 
colouring  in  flowers,  should  deny  its  attractive  nature  in 
the  question  of  sex. 

It  is  allowed  on  all  hands,  I  believe,  that  the  special 
odours  of  insects,!  as  well  as  their  stridulatingj  noises,^  are 
guides  to  the  sexes  in  their  search  for  one  another.  It 
does  not  appear  that  colour  stands  on  any  different  footing 
in  this  respect. 

Furthermore,  many  insects  have  two  sets  of  colours, 
apparently  for  different  purposes,  the  one  set  protective 

1  See  r.  Miiller  in  "  Nature,"  November  29,  1877. 

2  Darwin,  Descent  of  Man,  passim. 


DIRECT  RE  A  CTIOX.  1 59 

from  tlie  attacks  of  enemies,  the  other  set  attractive  for 
the  opposite  sex.  Thus  several  butterflies  have  the  lower 
sides  of  their  wings  protectively  coloured,  so  as  to  preserve 
them  from  the  notice  of  birds  or  lizards,  while  they  sit 
with  folded  wings  on  a  flower  or  leaf ;  whereas  the  upper 
sides  are  attractively  coloured,  and  displayed  in  the  open 
sunlight  as  they  flit  about  in  search  of  mates.  Moths, 
again,  whose  habits  of  folding  the  wings  are  exactly 
opposite,  often  have  their  upper  surfaces  imitative  or  pro- 
tective, while  tlie  under  sides  are  bright  and  beautiful 
Sometimes  the  union  of  protective  and  attractive  features 
in  the  same  insect  is  very  striking.  Thus  Mr.  WaEace 
himself  mentions  a  leaflike  butterfly,  Kallima  jparalekta, 
whose  w4ngs  are  purple  and  orange  above,  but  exactly 
mimic  dead  foliage  when  closed  ;^  this  insect  always  rests 
among  dead  or  dry  leaves,  and  imitates  every  stage  of 
decay,  being  even  apparently  spotted  with  small  fungi. 
So,  too,  Mr.  Bates  tells  us  of  a  grasshopper,  Pterochroza, 
whose  sheath-like  fore-wings  similarly  resemble  a  green 
leaf,  while  its  hind-wings,  usually  covered  except  during 
flight,  are  "  decorated  with  gaily-coloured  eyelike  spots."  ^ 
Again,  Mr.  Belt  observes  that  the  males  of  some  butterflies 
which  mimic  the  Heliconidae  are  coloured  with  black  and 
white,  quite  unlike  the  mimicking  females,^  while  some 
South  African  species  show  perfectly  marvellous  differ- 
ences in  this  respect.  In  all  these  cases,  one  cannot  but 
believe  that  while  the  one  form  of  colouring  has  been 
acquired  for  the  sake  of  protection,  the  other  must  differ 
from  it  for  some  sufficient  functional  purpose. 

Once  more,  there  seems  to  be  a  pretty  constant  connec- 
tion between  the  general  beauty  of  the  flora  in  any 
particular   district  and  the  general  beauty  of  its   insect 

1  Malay  Archipelago,  p.  131.  vious  truth  that  white  and  pale  yel- 

2  The  Naturalist  ou  the  Amazons,  low  are  really  very  brilliant  colours 
r-  145-  when  comi)ared  with  the    green   or 

3  Mr.  Wallace  seems  to  me  to  have  brown  of  ordinary  life.     See  "  Tropi- 
quite   perverted  the  simple  explana-  cal  Nature,"  p.  204. 

tion  of  this  fact  by  neglecting  the  ob- 


i6o  THE  COLOUR-SENSE. 

inhabitants.  Of  course,  it  lias  long  been  noted  that  where 
few  or  no  flying  insects  exist,  few  or  no  bright-coloured 
flowers  are  found.  But  what  I  wish  to  point  out  here  is 
the  converse  fact  that  where  bright  blossoms  are  common, 
insects  are  brilliant,  while  where  most  blossoms  are 
inconspicuous,  most  insects  are  dingy.  On  this  head 
the  mass  of  evidence,  though  difficult  to  quote,  is  over- 
whelming. A  few  of  the  more  striking  instances  may, 
however,  be  briefly  given  here.  On  the  whole,  the  brightest 
flowers  grow  among  the  tropics,  and  on  the  whole,  tropical 
insects  are  unusually  beautiful.  The  flora  and  the  minor 
fauna  of  Madagascar  are  equally  remarkable  for  their 
splendid  hues.  Sir  Joseph  Hooker  notices  the  extreme 
magnificence  of  the  Himalayan  flora;  and  he  also 
mentions  the  singular  loveliness  of  the  butterflies.^  Sir 
Emerson  Tennant  speaks  continually  of  the  beauty  of  the 
"  brilliant  flowering  shrubs  "  in  Ceylon,^  and  he  likewise 
speaks  of  the  beauty  of  its  butterflies  in  large  numbers.^ 
In  Mr.  Bates's  work  on  Brazil,  I  notice  almost  on  every 
page  the  conjunction  of  pretty  insects  with  striking 
flowers,  or  the  absence  of  both  together.*  Especially  does 
he  note  the  beauty  of  the  Longicorn  beetles  found  on 
flowers^  at  Caripi,  while  a  few  pages  before  he  remarks 
upon  the  abundance  of  exquisite  blossoms  at  the  same 
place.^  I  cannot  help  interpolating  here,  though  out  of 
proper  order,  the  remark  that,  just  in  like  manner,  he  seldom 
mentions  the  capture  of  a  handsome  bird  without  adding 
that  it  was  shot  in  a  fruit-tree.  Almost  the  only  bright 
butterfly  which  I  ever  observed  in  large  numbers  in 
Jamaica  was  the  Calliclryas  eubule,  feeding  on  the  abundant 
yellow  cactus  blossom,  whose  hue  it  exactly  resembled,  and 
which  is  the  only  common  and  conspicuous  large  entomo- 
philous  flower  in  the  colony.     Both  Mr.  Wallace  himself 

1  Himalayan  Journal,  i.    152,   and        ^  See  the  Naturalist  on  the  Ama- 
ii.  98.  zons,  pp.  20,  274, 

2  Ceylon,  pp.  87,  88,  92.  ^  Ibid,  p,  no. 
2  Ibid,  pp.  247,  248.                                 6  Ibid,  p.  loi. 


DIRECT  RE  A  CTION.  1 6 1 

and  Lord  George  Campbell,^  an  excellent  non-scientific 
observer,  remark  upon  the  beauty  of  the  insects  and 
flowers  of  the  Ke  Islands.  Similarly,  the  flowers  of 
Amboyna  are  paralleled  by  its  gorgeous  beetles,  butterflies, 
and  birds.^  On  the  other  hand,  in  ISTew  Zealand  "  there 
are  scarcely  any  gay  flowers  and  blossoms ;  but  few  her- 
baceous plants,  nothing  but  shrubs  and  trees;  shrubs 
with  obscure  green  flowers  ; "  ^  while  at  the  same  time  "  the 
butterflies  are  distinguished  neither  by  size  nor  by  richness 
of  colour."  *  Oceanic  islands,  which  have  few  or  no  bright 
flowers,  are  remarkable  for  the  absence  of  bright  insects ; 
and  Mr.  Darwin  mentions  of  the  Galapagos  group  both 
the  fact  that  he  "  did  not  see  one  beautiful  flower,"  and 
also  the  universal  dinginess  of  the  whole  fauna.  But  this 
question  is  one  on  which  it  is  difficult  to  quote  positive 
authorities :  it  must  rather  suffice  to  mention  that  a  con- 
siderable search  into  the  general  impressions  of  travellers 
— the  best  evidence,  after  all,  on  so  indefinite  a  point — has 
convinced  me  that  such  a  general  relation  does  actually 
obtain.  It  is  no  answer  to  say  that  the  insects  are  neces- 
sary for  the  production  of  the  flowers  :  the  real  point  at 
issue  is  this — why  are  insects  bright  where  bright  flowers 
exist  in  numbers,  and  dull  where  flowers  are  rare  or  in- 
conspicuous ?  We  can  hardly  explain  this  wide  coinci- 
dence otherwise  than  by  supposing  that  a  taste  for  colour 
is  produced  through  the  constant  search  for  food  among 
entomophilous  blossoms,  and  that  this  taste  has  reacted 
upon  its  possessors  through  the  action  of  unconscious 
sexual  selection. 

Finally,  it  would  seem  that  Mr.  Wallace's  own  theory 
of  "  typical  colours  "  really  allows  all  that  is  here  required. 
For  Mr.  Wallace  speaks  distinctly  of  the  "  need  of  recog- 
nition and  identification  by  others  of  the  same  species  "  ^ 

1  Log-Letters  from  the  Challenger,     133.     See  also  Six-  Joseph  Hooker's 
p.  187.  "Flora  of  New  Zealand,"  p.  28. 

2  Ibid.,  p.  208.  "*  Hochstetter,  p.  170. 

2  Hochstetter's   New   Zealand,   p.         ^  Tropical  Nature,  p.  215. 

L 


i62  THE  COLOUR-SENSE. 

as  one  among  the  determining  causes  of  sucli  colours,  not 
only  in  the  case  of  birds,  but  also  in  that  of  butterflies, 
four  families  of  which  he  specifies  by  name.     ISTow,  con- 
spicuousness  of  hue  is  certainly  a  very  simple  means  of 
identification :  and  I  think  we  must  allow  that  it  acts  as 
an  allurement  to  the  eye  in  the  case  of  flower-feeding 
species.     I  am  quite  disposed  to   accept  Mr.  Wallace's 
belief  that  the  actual  disposition  of  the  stripes,  spots,  and 
lines,  is  a  matter  of  special  typical  arrangement ;  but  even 
here  one  would  naturally  suppose  that  some  minute  cause 
must  at  first  have  led  to  the  preference  for  one  arrange- 
ment over  another.     Briefly,  to  sum  up  the  whole  question, 
after  making  full  allowance  for  warning  colours  and  for 
mimetic  or  other  protective  colours,  there  seems  to  remain 
a  large  margin  of   cases  in  which  brilliancy  exists  for 
purely  attractive  purposes :    while   often    the   attractive 
function  is   combined  with  more  or  less   of   protective 
device.     Anybody  who  watches  our  own  English  butter- 
flies on  a  sunny  day  can  hardly  doubt  that  display  forms 
a  part  of  the  object  for  which  their  yellow,  orange,  or 
crimson-spotted  wings  have  been  developed,  and  that  such 
display  makes  them  an  easier  mark  for  their  scattered 
mates.     Above  all,  it  is  necessary  to  remember  that  the 
winged  condition  in  these  insects  is  hardly  more  itself 
than  a  sexual  device  for  the  perpetuation  of  the  various 
species. 

And  now  let  us  pass  on  to  consider  the  fuller  evidence 
afforded  us  by  vertebrates. 

To  begin  with  fishes,  it  must  be  allowed  that  our  present 
knowledge  of  their  habits  scarcely  justifies  us  in  making 
any  distinct  inferences  from  their  colouring.  ISTevertheless, 
a  few  facts  may  perhaps  be  gleaned  even  here.  The  mass 
of  lower  marine  animals  are  brilliantly  coloured  with  what 
seem  to  be  purely  adventitious  or  protective  colours ;  and 
we  had  occasion  already  to  remark  upon  the  similarity 
between  their  hues  and  those  of  fungi,  saprophytes,  and 
other  like  vegetal  organisms.     As  a  few  examples  may 


DIRECT  RE  A  CTION.  163 

be  mentioned  sea-anemones,  star-fisli,  ecliini,  medusae, 
ascidians,  sea-slugs,  and  corals.  When  we  reach  the 
moUusca,  the  colouring  begins  to  assume  a  different  type, 
but  it  would  be  difficult  to  assign  any  sufficient  cause  ibr 
its  occurrence.  Amongst  the  marine  articulata,  and  espe- 
cially the  crustaceans,  many  species  exhibit  a  regularity 
of  hue,  and  minute  arrangement  of  spots  and  lines,  which 
seems  to  bespeak  a  certain  amount  of  sexual  selection. 
These  doubtful  instances,  however,  we  must  pass  over,  not 
because  they  are  less  interesting,  but  because  they  are  so 
very  uncertain ;  and  in  a  brief  examination  like  the  present, 
we  must  necessarily  confine  our  attention  to  the  most 
salient  points.  Now,  the  abundance  of  coloured  organisms, 
both  animal  and  vegetal,  in  the  sea,  affords  a  fair  ground 
for  belief  that  fishes  may  have  acquired  o^colour-sense,  and 
a  taste  for  bright  hues.  We  know  that  they  (as  well  as 
the  crustaceans)  can  be  attracted  by  crimson  or  scarlet 
rags,  and  that  glistening  objects  like  rnetals  or  artificial 
baits  rapidly  seize  upon  their  attention.  As  to  the 
brilliancy,  beauty,  and  regularity  of  their  colouring,  the 
reader  must  be  referred  to  Mr.  Darwin's  description  in 
the  "  Descent  of  Man,"  where  he  will  find  a  full  account  of 
the  principal  facts  which  go  to  prove  the  existence  among 
them  of  sexual  selection.  I  must  content  myself  here  by 
saying  that  for  gorgeous  colouring  and  variety  of  patterns 
they  are  nowhere  surpassed  in  the  whole  animal  kingdom; 
and  that  metallic  sheen  is  especially  conspicuous  among 
the  devices  whereby  they  insure  the  attention  of  their 
mates. 

As  regards  the  special  question  upon  which  we  are  now 
engaged,  a  few  facts  may  be  shortly  set  down.  In  the  first 
place,  the  lower  animals  of  tropical  seas  are  on  the  whole 
much  more  brilliantly  coloured  than  those  of  temperate 
climates,  and  the  same  remark  holds  good  of  the  fishes. 
Mr.  Darwin  has  noticed  the  extreme  beauty  of  the  shoals 
which  played  in  and  out  among  the  brilliant  organisms  of 
the  coral  lagoons;  and  though  Mr.  Wallace  objects  that 


1 64  THE  COLOUR-SENSE. 

tliis  may  be  due  to  protective  causes,  in  order  tliat  they 
may  escape  notice  among  the  bright  creatures  about  them, 
y^et  as  Mr.  Darwin  pertinently  replies,  he  was  struck  by 
the  obvious  conspicuousness  of  their  appearance  rather 
than  by  their  resemblance  to  environing  objects.  I  have 
myself  observed  the  same  point  frequently  in  the  West 
Indian  harbours,  where  the  fish  and  the  neioiibourincj 
creatures,  seen  through  clear  still  water,  all  appeared 
equally  beautiful  and  noticeable.  But  I  cannot  do  better 
than  quote  Mr.  Wallace's  own  description  of  the  harbour 
of  Amboyna.  "  The  bottom,"  he  says,  "  was  absolutely 
hidden  by  a  continuous  series  of  corals,  sponges,  actiniae, 
and  other  marine  productions  of  magnificent  dimensions, 
varied  forms,  and  brilliant  colours.  ...  In  and  out  among 
them  moved  numbers  of  blue  and  red  and  yellow  fishes, 
spotted  and  banded  and  striped  in  the  most  striking 
manner,  while  great  orange  or  rosy  transparent  medusa3 
floated  along  near  the  surface."  ^  And  elsewhere  he  ob- 
serves, "  The  fishes  (of  Amboyna)  are  perhaps  unrivalled 
for  variety  and  beauty  by  those  of  any  one  spot  on  the 
earth."  These  facts  at  least  tend  to  show  that  our  theory 
does  not  receive  any  active  contradiction  from  the  condi- 
tions of  marine  existence ;  and  they  are  confirmed  by 
numerous  other  like  passages  in  several  authors  whom  I 
think  it  superfluous  to  quote. 

On  the  other  hand,  the  larger  predatory  species,  such  as 
sharks  and  pikes,  together  with  the  majority  of  temperate 
fishes,  are  decidedly  wanting  in  brilliant  hues.  Mr.  Wallace 
observes  that  river  fish,  even  of  the  tropics,  rarely  if  ever 
have  gay  or  conspicuous  markings  ;  ^  and  this  is  just  what 
we  would  expect  from  the  nature  of  their  food,  consisting 
as  it  does  of  worms,  small  flies,  and  other  inconspicuous 
objects.  However,  we  must  allow  that  in  this  case  Mr. 
Wallace  has  witnessed  against  himself  with  excessive 
fervour ;    for   many   river    fish   undoubtedly   liave   very 

1  Malay  Archipelago,  p.  295. 
"  Contributions  to  the  Theory  of  Natural  Selection,  p.  55. 


DIRECT  REACTION.  165 

brilliant  colours,  as  I  can  especially  testify  from  having 
caught  in  my  youth  numbers  of  the  Canadian  sun-fish, 
perhaps  the  most  exquisite  creature  of  its  class  which  I 
have  ever  seen.  But  this  particular  species  lives  in  shallow 
marshy  water,  and  maij  have  derived  its  tastes  from  butter- 
flies and  dragon-flies.  Professor  Agassiz  speaks  much, 
too,  concerning  the  beauty  of  the  Amazonian  fishes,^  which 
he  describes  as  having  a  quasi-marine  character  ;  ^  and  in 
spite  of  a  possible  accusation  for  grotesqueness,  I  would 
venture  to  suggest  that  their  colouring  may  perhaps  be 
due  to  those  numerous  butterflies  which  Mr.  Bates  so  often 
describes  as  flitting  in  numbers  along  the  banks  of  that 
mighty  river.  However  this  may  be,  we  must  leave  these 
somewhat  inconclusive  cases,  and  hurry  on  to  the  terrestrial 
vertebrates. 

The  amphibia  yield  little  evidence  in  either  direction. 
The  beautiful  colouring  of  tree-frogs,  when  compared  with 
toads  and  common  frogs,  is  more  probably  protective  than 
attractive.  Still,  the  newts  show  us  very  unmistakable 
signs  of  sexual  selection  in  their  crests ;  and  we  cannot 
say  that  the  habits  of  amphibia  may  not  have  generated  a 
love  for  colour. 

Among  the  reptiles,  however,  a  good  many  facts  may 
be  quoted  to  our  purpose.  In  the  first  place,  the  large 
water-haunting  crocodiles  and  alligators  are  peculiarly 
dull  and  unsightly  objects;  while  the  whole  order  of 
Chelonia,  including  the  turtles  and  tortoises,  are  as  incon- 
spicuous for  colour  as  they  well  can  be.  On  the  other 
hand,  the  smaller  saurians,  many  of  which  lead  an  ar- 
boreal life,  and  feed  off  varied  food,  sometimes  fruit,  some- 
times insects  and  other  small  animals,  are  often  noticeable 
for  their  beauty.  Most  iguanas,  great  jungle  lizards,  con- 
trast strongly  in  hue  with  the  crocodiles  ;  but  one  species, 
AmUyrlujnclius  cristatus,  which  inhabits  the  dull-coloured 
Galapagos  Islands,  and  has  taken  to  a  strangely  abnormal 
marine   life,   is   remarkable   for   the  same  sombre  tints 

^  A  Journey  in  Brazil,  p.  184.  -  Ibid.,  p.  238. 


1 66  THE  COLOUR-SENSE. 

wliicli  characterise  the  other  animals  of  that  singular 
archipelago,  being  described  by  Mr.  Darwin  as  of  "  a  dirty- 
black  colour."  The  lesser  lizards  give  unmistakable 
proofs  of  sexual  selection  in  the  brilliant  pouches  which 
they  protrude  when  sunning  themselves,  and  whose  exqui- 
site colours  have  struck  every  observer.  Their  mechanism 
for  changing  the  hue  of  their  skin,  by  compressing  or 
spreading  the  layers  of  pigment  cells,  has  already  been 
noticed ;  and  it  seems  to  betray  a  considerable  sensitive- 
ness to  colour.  Dr.  Giinther  also  sees  reason  to  believe 
that  the  frugivorous  lizards  have  the  tongue  as  an  organ 
of  taste,  while  in  the  insectivorous  species  he  considers  it 
merely  an  organ  for  the  prehension  of  prey.^  Now,  a 
large  number  of  all  lizards  are  noticeable  for  their  exqui- 
site hues.  Green,  as  might  naturally  be  supposed,  from 
protective  reasons,  forms  the  general  groundwork  of  their 
colouring;  but,  as  often  happens  under  similar  circum- 
stances, many  other  shades  are  intermingled,  apparently 
to  perform  the  attractive  function.  Especially  is  this 
noticeable  in  the  Anolis  and  other  like  genera,  whose 
beautiful  orange  pouches  consist  of  folds  of  the  skin, 
which  are  concealed  under  ordinary  circumstances,  but 
protruded  for  display  when  the  animal  feels  himself 
secure,  and  can  sun  himself  at  leisure  on  a  dead  branch. 
The  family  of  Agamidm  include  many  of  the  most  bril- 
liant species,  especially  the  exquisite  Draco,  whose  beauty 
Mr.  Darwin  extols  so  highly  ;2  and  these,  says  Dr. 
Giinther,  are  arboreal  in  their  mode  of  life,  while  the  dull- 
coloured  genera  inhabit  rocks  or  plains.^  It  is  true  that 
Draco  feeds  on  insects;  but  when  we  remember  the 
beauty  of  many  among  these  little  tropical  creatures,  we 
see  fair  grounds  for  believing  that  its  habits  may  have  led 
it  to  form  a  taste  for  colour.     The  Geckos  also  eat  moths  ;  * 

^  Eeptiles  of  British  India,  p.  56.  amongst  butterflies,  birds,  these  liz- 

-  I  shiill  note  hereafter  the  singular  ards,  and   even  the  flying  squirrels, 

coincidence  betM^een  the  possession  of  &c. 

a  flying  apparatus  and  general  bril-         ^  Reptiles  of  British  India,  p.  120. 

liancy  of  hue,  which  seems  to  obtain        ■*  Giinther,  p.  100. 


DIRECT  REACTION.  167 

while  Mr.  Gosse  found  on  dissection  many  pretty  insects 
in  the  stomach  of  the  lovely  Yenus  lizard  of  the  West 
Indies.^  Here,  too,  we  may  even  see  the  indirect  effect 
of  flowers  and  fruits  ;  for  Mr.  Wallace,  after  noticing  the 
"  abundance  and  varied  colours  of  the  little  jumping  spiders 
w^hich  abound  on  flowers  and  foliage  (in  the  Aru  Islands), 
and  are  often  perfect  gems  of  beauty,"  2  goes  on  to  say 
about  the  lizards  in  the  same  place,  "  Every  rotten  trunk 
or  dead  branch  served  as  a  station  for  some  of  these 
active  little  insect-hunters,  who,  I  fear,  to  satisfy  their 
gross  appetites,  destroy  many  gems  of  the  insect  world, 
which  would  feast  the  eyes  and  delight  the  heart  of  our 
more  discriminatincj  entomoloofists."  ^ 

Among  snakes  we  find  somewhat  similar  facts.  W^hile 
the  arboreal  species,  still  having  green  for  their  ground- 
work, "  are  characterised  by  their  vivid  colouration,"  ^  the 
ground-snakes,  burrowing-snakes,  and  water-snakes  are 
mostly  dull  and  inconspicuous.  Of  the  ground-colubrides, 
in  particular.  Dr.  Glinther  says,  "  They  live  on  the  ground, 
and  are  generally  of  not  brilliant  colouration ;  only  a  few, 
which  frequent  grassy  plains,  are  of  a  bright  green 
colour."^  The  Dendrophidse  eat  lizards  and  like  prey, 
and  are  usually  very  bright ;  their  colours  sometimes,  as 
in  the  magnificent  Chrysopelea  ornata,  being  decidedly  not 
protective.  Of  course,  almost  all  arboreal  snakes  feed 
upon  various  foods,  such  as  birds,  smaller  reptiles,  or 
other  brilliant  animals,  whose  colours  may  have  served  to 
give  them  a  taste  in  that  direction.  I  confess  I  attach 
little  importance  to  any  of  these  cases ;  still  I  think  it 
worth  while  prominently  to  call  attention  to  the  fact  that 
most  arboreal  creatures  are  conspicuous  for  their  excep- 
tional brilliancy. 

Doubtless  much  of  the  bridit  colouration  in  all  these 

o 

animals  is  more  or  less  warning  or  protective.     Thus,  one 

1  The  Naturalist  in  Jamaica,  p,  145.         ■*  Gimtber,  p.  166. 
-  Malay  Archipelago,  \).  432.  5  ibid.,  p.  221. 

3  Ibid.,  p.  433. 


i68  THE  COLOUR-SENSE. 

may  mention  Mr.  Belt's  "little  frog  that  hops  about  in 

the  daytime,  dressed  in  a  bright  livery  of  red  and  blue."  ^ 

Mr.  Belt  suspected  this  species  to  be  inedible,  from  the 

staring  nature  of  its  hues ;  accordingly,  he  offered  one  to 

some  ducks,  but  only  succeeded  in  making  one  young  duck 

bite  it  amongst  some  meat ;  and  the  bird  "  instantly  threw  it 

out  of  its  mouth,  and  went  about  jerking  its  head  as  if 

trying  to  throw  off  some  unpleasant  taste."     Then,  again, 

there  are  the  coral-snakes  of  South  America,  for  which 

Mr.  Darwin  has  fully  accounted.     Once  more  Mr.  "Wallace, 

in  his  "  Contributions  to  the  Theory  of  Natural  Selection," 

has  pointed  out  that  green  lizards  frequent  trees,  while 

many  Geckos  are  so  marbled  as  to  resemble  the  bark  on 

which  they  crawl.^      Mr.  Belt   speaks   also  of   a  green 

Mcaraguan  species,  which  looks  exactly  like-  the  herbage 

among  which  it  lurks,  and  has  actually  acquired  leaf-like 

expansions  to  deceive  its  prey.^     Mr.  Bates,  too,  notices  a 

pale-green  snake  {Dryopliis  fulgida)  so  perfectly  imitating 

the  stem  of  a  liana  that  it  deceived  even  his  practised  eye 

at  first  sight ;  ^  and  we  must,  doubtless,  refer  to  the  same 

cause  the  verdant  colour  of  the  grass-snakes  mentioned  by 

Dr.  Gtinther.     But  the  noticeable  point  here,  as  in  the  case 

of  the  butterflies,  is  thi.s,  that  while  we  find  a  prevailing 

imitative  greenness,  apparently  for  protective  purposes,  we 

so  often  find  a  mixture  of  crimson,  blue,  yellow,  orange,  or 

metallic  iridescence,  whose  function  seems  to  me  purely 

attractive.     We  shall  notice  similarly,  when  we  come  to 

look  at  the  parrots,  that  their  prevailing  ground-tint  is 

likewise  green,  but  that  they  indulge  in  every  variety  of 

brighter   pigments   in   a  decidedly  conspicuous   manner. 

My  own  observation  of  West  Indian  lizards  would  certainly 

lead  me  to  say  that  their  colours  were  far  more  likely  to 

betray  them  than  to  protect  them,  even  in  their  native 

haunts. 

^  Naturalist  in  Nicaragua,  p.  321.  ^  Naturalist  in  Nicaragua,  p.  12. 

2  See  also  Tropical  Nature,  p.  iii,         ^  Naturalist  on  the  Amazons,  p. 
seq.  99. 


DIRECT  REACTION.  169 

Birds,  however,  offer  the  best  evidence  of  alh  It  will 
be  desirable  to  mark  briefly  the  most  conspicuous  instances, 
and  then  to  give  the  minor  cases  in  detail. 

The  birds  of  prey — eagles,  hawks,  and  falcons — and  the 
carrion  birds — vultures,  condors,  and  (since  we  are  speak- 
ing of  habits  only)  ravens  or  adjutant  storks — are  all  dull 
greyish  or  blackish  birds,^  and  their  colouring  may  be  com- 
pared to  that  of  the  flies  and  crocodiles.  Nocturnal  birds, 
again,  such  as  owls  and  goat-suckers,  show  considerable 
analogies  to  moths  and  other  night-flying  insects.^  In 
fact,  aU.  the  raptores,  of  whatever  habit,  and  almost  all 
birds  of  similar  habit  elsewhere,  are  nearly  or  quite  desti- 
tute of  decorative  colouring. 

On  the  other  hand,  among  the  insessores  we  find  an 
immense  number  of  the  most  brilliant  of  all  organic 
creatures.  Especially  remarkable  are  the  humming-birds 
and  the  sun-birds.  Now,  Prince  Lucien  Bonaparte  has 
abundantly  shown  that  the  former  family  are  really  the 
allies  of  our  dingy  northern  swifts,  and  that  the  sun-birds 
are  not  at  all  connected  with  them  genetically.  But  both 
families  feed  upon  the  mixed  nectar  and  insects  which 
they  catch  in  bright-coloured  entomophilous  flowers,  and 
both  are  equally  noticeable  for  their  exquisite  metallic 
gloss,  their  varied  hues,  and  the  profusion  of  their  decora- 
tive devices,  such  as  crests,  ruffs,  feather  lappets,  and  long 
tail-plumes.  Is  it  not  a  significant  fact  that  these  two 
families,  one  in  the  western  hemisphere  and  the  other  in 
the  eastern,  separately  developed  from  dingy  ancestors, 
should  have  acquired  exactly  the  same  exquisite  plumage 
under  exactly  like  conditions  of  food  ?  We  can  hardly 
resist  the  inference  that  a  taste  for  colour  has  been  aroused 

1  I  am  aware  that  all  sucli  general-  its  ensemble,  and  not  to  look  at  single 

isatious  will  be  attacked  by  bringing  cases. 

up  isolated  instances,   such    as  the  -  While    following    approximately 

king- vulture,  who  may  lay  some  claim  the  real  biological  order  in  these  cases, 

to  be  moderately  coloured  ;  but  I  must  I  do  not  scruple  to  introduce  analo- 

beg  the  reader  to  take  each  group  in  gous  instances  from  any  other  tribe 

when  necessary. 


170  THE  COLOUR-SENSE, 

in  their  constant  search  after  flowers,  and  that  this  taste 
has  reacted  through  sexual  selection  upon  their  own 
appearance. 

JSText  in  importance  to  these  two  families  come  the 
parrot  group.  These  are  either  fruit-eaters,  or  else,  as  in 
the  case  of  the  lories,  they  feed  upon  nectar.  And  here  I 
venture  to  borrow  Mr.  Wallace's  words.  "No  group  of 
birds,"  says  he — "perhaps  no  other  group  of  animals — 
exhibits  within  the  same  limited  number  of  genera  and 
species  so  wide  a  range  and  such  an  endless  variety  of 
colour.  As  a  rule  parrots  may  be  termed  green  birds,  the 
majority  of  the  species  having  this  colour  as  the  basis  of 
their  plumage,  relieved  by  caps,  gorgets,  bands,  and  wing- 
spots  of  other  and  brighter  hues.  Yet  this  general  green 
tint  sometimes  changes  into  light  or  deep  blue,  as  in  some 
macaws;  into  pure  yellow  or  rich  orange,  as  in  some  of 
the  American  macaw-parrots  (Conurus) ;  into  purple,  grey, 
or  dove-colour,  as  in  some  American,  African,  and  Indian 
species ;  into  the  purest  crimson,  as  in  some  of  the  lories ; 
into  rosy-white  and  pure  white,  as  in  the  cockatoos ;  and 
into  a  deep  purple,  ashy  or  black,  as  in  several  Papuan, 
Australian,  and  Mascarene  species.  There  is  in  fact  hardly 
a  single  distinct  and  definable  colour  that  cannot  be  fairly 
matched  among  the  390  species  of  known  parrots.  Their 
habits,  too,  are  such  as  to  bring  them  prominently  before 
the  eye.  They  usually  feed  in  flocks  ;  they  are  noisy,  and 
so  attract  attention  ;  they  love  gardens,  orchards,  and  open 
sunny  places ;  they  wander  about  far  in  search  of  food, 
and  towards  sunset  return  homewards  in  noisy  flocks,  or 
in  constant  pairs.  Their  forms  and  motions  are  often 
beautiful  and  attractive.  The  immensely  long  tails  of  the 
macaws,  and  the  more  slender  tails  of  the  Indian  parra- 
quets ;  the  fine  crest  of  the  cockatoos ;  the  swift  flight  of 
many  of  the  smaller  species,  and  the  graceful  motions  of 
the  little  love-birds  and  allied  forms ;  together  with  their 
affectionate  natures,  aptitude  for  domestication,  and  powers 
of  mimicry — combine  to  render  them  at  once  the  most 


DIREC  T  RE  A  CTION.  j  7 1 

conspicuous  and  the  most  attractive  of  all  tlie  specially 
tropical  forms  of  bird-life."  ^ 

Even  the  minor  variations  of  these  three  great  groups — 
the  humming-birds,  the  sun-birds,  and  the  parrots — show 
us  a  like  result.  For  there  is  one  sub-family  of  the  former 
group — the  Phaethornidas — which  have  not  taken  to  flower 
haunting,  but  which  catch  minute  insects  on  exposed 
situations;  and  these  are  described  by  Mr.  Wallace,  not 
in  that  language  of  sapphire,  ruby,  and  amethyst  which  is 
lavished  on  their  congeners,  but  simply  as  "  small  brown 
humming-birds." 2  "The  members  of  all  these  genera," 
says  Mr.  Gould  in  his  magnificent  work  on  the  Trochilidse, 
"  are  remarkable  for  being  destitute  of  metallic  brilliancy, 
and,  as  their  trivial  name  of  '  hermits '  implies,  for  affect- 
ing dark  and  gloomy  situations.  They  constitute  perhaps 
the  only  group  of  the  great  family  of  humming-birds  which 
frequent  the  interior  of  the  forests,  and  there  obtain  their 
insect  food — some  from  the  underside  of  the  leaves  of  the 
great  trees,  while  others  assiduously  explore  their  stems 
in  search  of  such  lurking  insects  as  may  be  concealed  in 
the  crevices  of  the  bark.  It  has  been  said  that  spiders 
constitute  the  food  of  many  species  of  this  group."  And 
he  adds  significantly  a  few  lines  further  down,  "  in  the 
colouration  of  their  plumage  both  sexes  are  generally 
alike."  ^  Then,  again,  we  learn  of  the  Arachnotherae,  or 
spider-hunters,  "  which  are  sun-birds  without  any  metallic 
or  other  brilliant  colouring,"  that  they  hunt  for  food  among 
the  anemophilous  and  uncoloured  blossoms  of  the  palm- 
trees.*  So,  too,  among  the  sombre  vegetation  of  New  Zea- 
land an  anomalous  night-parrot  {Strigaps  hctbroptilus)  is 
found,  which  lives  in  crevices  of  the  ground,  or  in  rocks 

1  Tropical  Nature,  p.  100.  argument    here    employed,    for    the 
-  Ibid.,  p.  136.                                          brilliant  mass  of  colour  would  natu- 

2  JMonograph.    of    the    Trochilidse,     rally  he  to  them  the  empirical  symbol 
Introduction,  p.  36.  of  food,  and  they  cannot  possibly  dis- 

^  Of    course   the   other  humming-  tinguish   between   the   circumstances 

birds  and  sun-birds  also  live  mainly  which  lead  to  the  presence  of  honey 

upon   insects   found  in   flowers,    but  and  of  insects  in  the   blossoms  they 

this    does  not  militate    against  the  suck. 


172  THE  COLOUR-SENSE. 

and  tree-roots,  only  coming  out  after  dark,  and  its  colour 
is  spoken  of  as  "  dull  yellowish  green."  ^  Bfere  one  may 
feel  almost  certain  that  the  primitive  bright  hue  has  be- 
come faded  and  dingy  owing  to  the  altered  habits  of  the 
bird,  which  would  effectually  prevent  the  action  of  sexual 
selection. 

Scarcely  less  interesting  are  the  group  of  pigeons, 
which  fall  under  two  principal  heads,  so  far  as  our  present 
purpose  is  concerned,  the  fruit-pigeons  and  the  ground- 
pigeons.  The  former  class  are  extremely  brilliant  in  their 
colouring,  comprising  a  large  number  of  the  most  beauti- 
ful knoAvn  birds ;  while  the  latter  almost  always  display 
sombre  dove-colours,  slates,  and  browns.^  ]N"ow,  the  fruit- 
pigeons  are  "especially  arboreal  in  their  habits,"  and 
"  their  nourishment  consists  for  the  most  part  of  fruits  :" 
while  the  ground-pigeons  feed  almost  entirely  on  seeds. 

The  toucans  form  another  group  in  which  like  adapta- 
tions occur.  They  live  nearly  altogether  upon  fruits, 
though  they  also  devour  birds'  eggs,  fish,  reptiles,  and 
insects,  to  a  slight  extent.  The  exquisite  colours  wdiich 
adorn  their  large  bills,  besides  the  varied  black,  white, 
green,  red,  and  yellow  of  their  plumage,  are  well  enough 
known  to  call  for  no  further  detail.^ 

Several  other  families,  allied  to  one  or  other  of  the 
preceding  groups,  are  almost  equally  noticeable  for  their 
magnificent  colouration.  First  on  the  list  may  come  the 
Australian  honey-suckers,  and  the  plantain-eaters  of 
Africa,  whose  name  sufficiently  proclaims  their  habits. 
I^ext,  we  may  place  the  allied  genus  of  Touracos,  "  gene- 
rally of  a  green  colour,  with  the  quill  feathers  of  the  wing 
and  tail  violet  or  red."  The  birds-of-paradise,  too  well 
known  to  need  description,  feed  on  fruits,  though  some 
species  are  flower-suckers.     The  barbets,  known  by  such 

1  Hochstetter's    New   Zealand,   p.  3  gee   on  the  colours  and  food  of 

167.  toucans,  Gould,  "Monograph  of  the 

-  Jerdon,  Bii'ds  of  India,  vol.  ii.  p.  Eamphastid*,"i9<mm. 
446. 


DIRECT  REACTION.  173 

expressive  names  as  golclen-throated,  blue-tliroated,  crim- 
son-breasted, and  so  forth,  live  almost  exclusively  on 
fruits  and  the  buds  of  flowers.  The  ornithological  reader 
will  have  no  difficulty  in  filling  in  other  cases  for  himself. 

Again,  many  of  the  tropical  birds,  less  brilliant  on  the 
whole  than  these  pure  vegetable-feeders,  yet  still  remark- 
able for  beautiful  colouration,  live  upon  a  mixed  diet  of 
fruits,  tropical  insects,  eggs,  lizards,  and  other  bright-hued 
foods.  "  Owing  to  the  prevalence  of  forests  and  the 
abundance  of  flowers,  fruits,  and  insects,"  says  Mr. 
"Wallace,  "  tropical,  and  especially  equatorial,  birds  have 
become  largely  adapted  to  these  kinds  of  food ;  while  the 
seed-eaters,  which  abound  in  temperate  lands,  where 
grasses  cover  much  of  the  surface,  are  proportionately 
scarce."  To  this  cause,  I  believe,  we  may  trace  the  general 
brilliancy  of  tropical  as  compared  with  temperate  birds, 
especially  among  the  great  groups  of  passeres  and  picarise. 

Among  other  instances,  which  I  can  only  note  briefly, 
may  be  mentioned  the  trogons,  w^hich  are  in  all  cases 
conspicuous  for  their  varied  beauty ;  but  those  which  in- 
habit America  are  more  gorgeous  than  the  Indian  species  ; 
and  fruit  forms  part  of  the  diet  among  the  former,  while 
that  of  the  latter  is  mainly  composed  of  insects. ^  Mr. 
Gould  mentions  that  the  stomach  of  T.  collaris  contained 
on  dissection  "  fruits  and  caterpillars."  ^  The  swallows 
of  temperate  climates  are  plainly  coloured,  as  might  be 
expected  from  the  nature  of  their  food ;  but  their 
allies,  the  rollers,  decked  in  gorgeous  violet,  blue,  and 
green,  live  upon  "insects  and  fruits"  in  sub-tropical 
countries :  and  with  them  may  be  included  the  exquisite 
todies,  with  their  green  plumage  and  gay  scarlet  breasts.^ 
The  lovely  motmots  of  tropical  America  and  the  West 
Indies  feed  upon  insects,  fruits,  and  lizards.*     The  diet  of 


1  Jerdon,  Birds  of  India,  vol.  i.  p.     voc.    See  also  under  T.  mdanopterus 
200.  and  T.  pavoninus. 

2  Monograph  of  the  Trogonidse,  suh        '  Gray,  Genera  of  Bird-',  i.  62. 

4  Ibid.,  i.  77. 


174  THE  COLOUR-SENSE, 

i\\Q  Eiirylcdmus  is  described  as  consisting  of  "insects,  at 
times  berries  and  fruits."  ^  The  omnivorous  crow  family 
are  dingy  creatures,  usually  with  no  colouring  save  black 
and  white ;  but  their  near  relations,  the  jays,  have  a  much 
more  vegetal  diet,  and  are  often  decorated  with  very 
striking  colours.  In  summer  they  "  visit  gardens,  tempted 
by  tlie  cultivated  fruits,"  and  they  also  feed  on  eggs  and 
insects.  The  hornbills  live  almost  entirely  on  fruit  and 
eggs ;  and  their  large  beaks  are  coloured  somewhat  after 
the  same  fashion  as  the  toucans.  But  I  shall  not  extend 
this  list,  which  might  be  easily  enlarged  with  numberless 
other  instances.  I  shall  ask  the  reader  instead  to  glance 
over  any  ornithological  work,  and  to  notice  the  universal 
coincidence  of  coloured  food  and  coloured  plumage  for 
himself.^ 

On  the  other  hand,  most  of  the  seed -eating  and  omni- 
vorous birds  are  dull  brown,  black,  or  otherwise  dingy  in 
their  plumage.  All  our  own  small  field-birds  may  be 
roughly  included  under  this  generalisation.  Such  are  the 
starlings,  finches,  sparrows,  larks,  thrushes,  ouzels,  wag- 
tails, titmice,  nightingales,  swallows,  and  martins.  Many 
of  these  live  upon  seeds  and  grains;  others  search  for 
larvae,  insects,  mollusca,  and  other  small  animals,  often 
amid  dung  or  like  refuse.  Even  amongst  these,  we  find 
instances  which  bear  out  our  general  theory.  Thus  the 
thrushes  as  a  rule  are  very  modest  in  their  plumage ;  but 
the  fruit-feeding  orioles  have  comparatively  bright  hues. 
So,  too,  while  most  of  the  finches  are  plainly  clad,  the 
forestine  rose-finches  have  exquisite  tints  of  pink  and 
crimson.  Ac^ain,  among:  our  owm  birds,  the  few  briditer- 
coloured  species  point  somewhat  in  the  same  direction : 
for  the  bullfinch,  the  most  notable  of  them,  has  very 
arboreal  habits,  feeds  upon  various  berries,  and  attacks 
flower-buds  in  gardens  to  such  an  extent  that  it  has  be- 

1  Gray,  Genera  of  Birds,  i.  6'S-  for  inclusion  here  in  full,   so  I  have 

2  I  find  the  number  of  cases  col-  only  selected  hap-hazard  a  few  of  the 
lected  in  nij  notes  quite  too  bulky    most  striking. 


DIRECT  RE  A  CTION.  175 

come  a  perfect  nuisance  to  gardeners  :  and  I  find  the  food 
of  the  Bohemian  chatterer  specified  as  consisting  of  "  the 
berries  of  the  mountain  ash,  hawthorn,  and  ivy,"  toojether 
with  the  fruit  of  the  juniper. 

Intermediate  between  these  two  classes  of  brilliant  and 
dingy  birds  come  a  number  of  moderately-beautiful  tribes, 
some  of  which  nearly  equal  the  parrots  and  humming- 
birds, while  others  scarcely  rise  above  the  level  of 
European  song-birds.  The  birds  of  this  division  are 
more  or  less  forestine  in  their  habits,  live  amid  a  very 
varied  environment,  and  feed  upon  insects  (often  very 
brilliant)  or  vegetal  matters,  including  seeds,  fruits,  bulbs, 
flower-buds,  and  leaves.  Besides  the  rollers,  todies,  and 
motmots  already  mentioned,  we  may  class  here  the 
cuckoos,  wood  -  peckers,  pastors,  grossbeaks,  manakins, 
pacJiyccphalincG,  flycatchers,  hoopoes,  bee  -  eaters,  jaca- 
mars,  and  kingfishers.  It  would  take  up  too  much  space 
to  specify  all  instances  in  full ;  but  I  have  satisfied  my- 
self that  a  general  connection  may  be  traced  amongst 
them  all,  on  the  average,  between  bright  food  and  pretty 
colourim:^. 

The  cases  so  far  examined  belong  to  the  great  central 
group  of  birds  which  composes  the  common  orders 
Columbne,  Scansores,  and  Passeres  :  we  may  glance  briefly 
at  the  more  divergent  orders,  whose  habits  have  produced 
a  very  different  structure.  The  swimming  birds,  with 
webbed  feet,  are  seldom  conspicuous  for  their  colouring. 
The  marine  species  (as  penguins,  auks,  puffins,  grebes, 
gulls,  and  albatrosses)  are  more  or  less  whitish,  with 
a  toning-down  of  black  or  grey.  But  the  ducks  and 
flamingoes,  which  live  amid  a  much  more  varied  environ- 
ment, and  feed  off  more  diversified  food,  are  often  adorned 
with  conspicuous  colours.  Tliese,  I  confess,  cannot  always 
be  explained  by  our  present  principle. 

The  wading  birds  (snipes,  storks,  cranes,  herons)  display 
for  the  most  part  only  cinereous  or  other  dingy  plumage. 
Psoiohia,  however,  a  brilliant  South  American  crane,  is  a 


176  THE  COLOUR-SENSE. 

tropical  forestine  bird,  and  feeds  on  fruits  and  grains.^ 
The  scarlet  ibis  of  the  Amazons  has  also  the  common  bril- 
liancy of  its  country,  which  may  be  equally  noticed  in  the 
roseate  spoonbill.  Here,  as  elsewhere,  I  must  ask  the 
reader  to  take  each  order  or  family  in  the  mass,  omitting 
such  aberrant  cases  as  do  not  readily  admit  of  explanation. 

The  running  birds  (ostriches,  emus,  cassowaries,  apteryx) 
have  little  beauty  of  colouring.  The  most  brilliant  among 
them,  the  cassowary,  whose  naked  head  and  neck  are 
tinted  with  red  and  blue,  is  also  the  most  frugivorous  of 
its  order,  feeding  upon  fruits,  herbage,  and  seeds  ;  while 
the  dingiest  of  all,  the  apteryx,  has  purely  nocturnal 
habits,  and  feeds  upon  insects. 

The  only  real  difficulty  is  presented  by  the  gallinaceous 
birds,  and  these  must  be  allowed  at  first  sight  to  offer  a 
great  obstacle  to  our  theory.  But  even  here  a  little  con- 
sideration considerably  modifies  the  opinion  we  form  at 
a  cursory  glance.  To  begin  with,  most  species,  like  the 
grouse,  partridges,  quails,  and  guinea-fowls,  are  by  no 
means  remarkable  for  the  purity  or  intensity  of  their  hues. 
There  is  really  only  one  family,  that  of  the  Phasianidae  or 
pheasants,  including  the  turkeys  and  peacocks,  which  can 
lay  claim  to  much  beauty  on  the  score  of  colour.  Even 
among  the  pheasants  themselves  many  species  are  far 
from  brilliant ;  and  when  we  come  to  compare  the  whole 
family  with  that  of  the  parrots  or  the  humming-birds,  we 
shall  find  that  the  peacock  alone  can  fairly  come  into  com- 
petition with  the  typical  fruit-eaters  and  flower-feeders. 
Moreover,  the  pheasants  as  a  group  are  thoroughly  fores- 
tine  birds  ;  they  pass  their  life  in  the  midst  of  brilliant 
objects,  and  many  of  these  serve  them  as  food.  Turkeys 
in  the  wild  state  feed  on  grain,  berries,  fruits,  grass,  and 
insects,  being  especially  fond  of  locusts  and  grasshoppers. 
The  diet  of  the  true  pheasants  comprises  the  same  varied 
items,  and  Yarrell  mentions  blackberries,  sloes,  haws,  and 
acorns  as  among  their  favourite  viands  in  English  copses. 

^  Gray,  Genera  of  Birds,  iii.  550. 


DIRECT  RE  A  CTION.  i  /  7 

The  forests  of  the  Himalayas  and  of  the  Malay  Archi- 
pelago, with  their  great  brilliant  fruits  and  flowers,  and 
their  exquisite  insects,  form  the  haunts  of  the  most 
beautiful  species  of  pheasants.  The  peacock  in  the  wild 
state  is  also  a  jungle-frequenter,  and  feeds  upon  grain, 
fruits,  and  insects.  On  the  whole,  I  think  it  may  be 
fairly  said  that  the  gallinaceous  birds,  though  not  strong 
supports  for  our  general  theory,  may  be  regarded  as 
friendly  neutrals  at  least.  The  dingy  species  are  skulkers 
in  underbrush,  who  feed  off  small  grain,  seeds,  bulbs,  and 
insects;  while  the  brilliant  species  are  tropical  or  sub- 
tropical forestine  birds,  whose  food  comprises  many  bright- 
coloured  objects,  both  animal  and  vegetal.^ 

Passing  on  to  the  mammalia,  we  find  facts  of  the  same 
sort  presented  on  every  side.  The  whole  lower  series, 
whether  among  marsupials,  pachyderms,  cetacea,  rumi- 
nants, carnivora,  or  insectivora,  show  us  almost  uniformly 
tints  of  black,  brown,  grey,  or  dingy  yellov\\  It  is  true 
that  many  animals,  like  the  zebras,  tigers,  spotted  deer, 
and  giraffes,  have  very  noticeable  alternations  of  light  and 
dark  shades,  but  they  do  not  yield  us  pure  spots  of  green, 
blue,  red,  or  yellow.  When  we  come  to  the  essentially 
arboreal  mammals,  however,  the  tree  rodents  and  the 
quadrumana,  we  get  many  comparatively  brilliant  species. 
The  squirrels  are  often  remarkable  for  their  beautiful 
colours,  and  the  so-called  flying- squirrels  call  for  special 
notice  in  this  respect.  The  contrast  between  these  pretty 
little  creatures  and  their  allies,  the  mice,  rats,  beavers,  and 
water-voles,  strongly  brings  out  the  peculiarity  of  their 
hues.  So,  too,  the  purely  frugivorous  monkeys  give  us 
a  variety  of  colour  which  we  find  nowhere  else  among  the 
mammalia :  and  in  the  scarlet  faces  of  many  among  them, 
or  most  remarkably  of  all  in  the  bright  red  and  blue  of 


1  It  is  worthy  of   note  that  one     other  swimmers,   while  its  external 
Sub-Antarctic  species,  Chionis  alba,     configuration  long  caused  it  to  be 
living  on  the  sea-shore,  has  the  cha-     included  among  the  waders, 
racteristic  colouring  of  the  gulls  or 

2kl 


178  THE  COLOUR-SENSE. 

the  mandrill,  we  have  the  only  'pure  tints  which  are  to  be 
found  in  the  whole  class.  Compared  with  the  nocturnal 
bats,  we  see  at  once  the  action  of  sexual  selection. 

Lastly,  I  should  like  to  add  that  while  I  attribute 
special  importance  to  the  nature  of  the  food,  I  do  not 
deny  that  the  whole  environment  must  have  a  consider- 
able modifying  influence  upon  the  tastes,  and  therefore 
upon  the  colouration  of  each  species;  and  accordingly 
I  freely  allow  the  general  truth  of  my  friend  Mr.  Eomanes' 
theory  upon  this  subject,  though  I  cannot  agree  with  him 
in  settino-  down  the  growth  of  tastes  to  mere  association. 

I  am  aware  that  this  long  catalogue,  by  mixing  up  the 
more  certain  with  the  less  certain  instances,  has  presented 
the  evidence  in  its  weakest  light.  To  redress  the  balance, 
then,  let  us  recapitulate  the  main  facts  from  another  point 
of  view. 

Mowers  are  the  most  brightly-coloured  of  all  vegetal 
productions.  Among  the  creatures  which  find  their  food 
in  flowers  may  be  mentioned  butterflies,  the  most  brightly- 
coloured  of  all  insects,  besides  humming-birds  and  sun- 
birds,  the  most  brightly-coloured  of  all  vertebrates.  Other 
flower-haunting  insects  are  the  rose-beetles,  loveliest  of  all 
the  Coleoptera,  and  many  more  of  the  handsomest  species. 
Other  flower-haunting  birds  are  the  lories,  far  the  most 
beautiful  among  the  parrot  tribe,  and  some  of  the  birds-of- 
paradise.  The  pretty  little  barbets  also  feed  in  part  on 
flowers.  The  butterflies,  rose-beetles,  humming-birds,  sun- 
birds,  and  lories  have  been  highly  modified  in  adaptation 
to  the  blossoms  in  which  they  find  their  food. 

Fruits  rank  second  in  beauty  among  vegetal  organs. 
First  in  the  list  of  creatures  which  feed  upon  fruits  may 
be  mentioned  the  whole  tribe  of  parrots,  macaws,  and 
cockatoos,  the  brightest  in  hue  of  all  birds,  except  the 
flower-feeders.  Xext  we  may  place  the  toucans,  with 
their  gaudy  beaks,  and  with  them  the  hornbills.  Then 
come  the  fruit-pigeons,  whose  gorgeous  tints  contrast 
strongly  with  those  of  their  seed-eating  congeners.     After 


DIRECT  REACTION,  197 

these  succeeds  a  whole  host  of  orioles,  blue-birds,  birds- 
of-paradise,  plantain-eaters,  and  less  conspicuous  fruit- 
feeders,  every  one  of  whom  has  some  beauty  of  colouring 
which  recalls  its  habitual  food.  Again,  the  frugivorous 
bats,  and  the  fruit-eating  quadrumana,  including  the 
gorgeous  mandrill,  are  the  most  highly-coloured  of  the 
mammalia.  Finally,  the  frugivorous  lizards  must  not  be 
forgotten  among  the  list.  Of  these,  the  parrots,  toucans, 
and  fruit-pigeons  have  been  specially  modified  to  suit 
their  peculiar  food. 

Third  in  point  of  colouring  we  may  place  the  insects 
themselves,  which  have  based  their  own  beauty  upon  that 
of  the  flowers.  The  creatures  which  prey  upon  these  may 
be  divided  into  two  classes,  the  partly  frugivorous,  and  the 
wholly  insectivorous.  Among  the  former  we  may  specially 
note  as  brilliantly-coloured  the  rollers,  todies,  motmots, 
many  trogons,  hoopoes,  some  birds-of-paradise,  and  jays. 
Among  the  latter  we  may  note  the  dragon-flies  and  tiger- 
beetles,  in  the  insect  world  itself;  the  jacamars,  bee-eaters, 
fly-catchers,  and  many  other  bright  small  kinds  of  birds  ; 
and  the  Draco,  with  many  less  brilliant  lizards.  On  the 
whole,  these  various  animals  are  inferior  in  beauty  of 
colour  to  the  flower-feeders  or  fruit-eaters,  but  are  still 
very  bright  in  their  hues.  It  should  be  further  noted  that 
most  of  them  are  closely  allied  with  frugivorous  or  flower- 
haunting  species,  from  which  they  may  in  some  cases  be 
descended,  and  that  many  live  habitually  in  the  midst  of 
an  environment  distinguished  for  the  general  brilliancy  of 
its  colours. 

Next,  we  may  descend  to  these  same  creatures  them- 
selves, looked  upon  as  tertiary  causes  of  colouring  in 
others.  Among  the  bright  objects  which  feed  upon  these 
birds  or  reptiles  may  be  noticed  many  brilliant  snakes  and 
some  lizard-eating  birds.  These,  too,  live  amid  an  environ- 
ment of  considerable  beauty. 

Last  on  the  list  we  may  place  the  marine  creatures, 
fishes  or  crustaceans,  which  pass  their  time  among  the 


i8o  THE  COLOUR-SENSE. 

gorgeous  productions  of  tropical  seas,  and  whose  own 
colouring  may  possibly  reflect  that  of  their  varied  and 
exquisite  surroundings. 

Now  let  us  look  at  the  reverse  picture  of  those  classes 
which  are  specially  deficient  in  pure  and  conspicuous 
colouring. 

First  in  order  of  ugliness  must  be  placed  the  carrion- 
feeders,  who  live  upon  decaying  bodies  or  animal  excre- 
ments. Among  insects,  we  may  notice  the  flies  which 
swarm  about  carcasses  or  dung,  several  dingy  beetles,  and 
all  the  other  ugly  creatures  which  we  always  surprise  in 
such  situations.  Among  birds,  the  vultures,  condors, 
turkey-buzzards,  and  other  like  obscence  voluci-es,  show  cor- 
respondingly dull  colours.  Among  mammals,  the  hyenas 
and  jackals  may  fall  nearly  under  the  same  category. 
It  is  worth  notice  that  all  these  creatures  have  for 
naturally  frugivorous  man  a  certain  weird  and  uncanny 
appearance,  which  seems  not  entirely  dependent  upon  as- 
sociation with  their  hideous  mode  of  life.  It  may  also  be 
observed  that  those  races  of  mankind  which  have  most 
fully  adopted  the  habit  of  feeding  upon  carrion  or  filthy 
prey,  such  as  worms,  insects,  &c.,  are  often  the  blackest, 
most  squalid,  and  least  aesthetic  of  the  whole  human 
species.^ 

Second  in  dinginess  rank  the  nocturnal  animals.  Among 
insects,  we  have  the  moths,  and  many  such  tribes  as  ear- 
wigs and  cockroaches.  Among  birds,  we  get  the  owls 
which  exactly  reproduce  the  moths  in  colour ;  besides  the 
goat-suckers,  the  apteryx,  and  numerous  other  aberrant 
types.  Among  mammals,  we  liave  the  mass  of  bats,  and 
several  quadrumanous  animals.  All  these  are  remarkable 
for  a  certain  general  murkiness  of  hue,  which  cannot 
otherwise  be  described,  but  which  can  be  felt  as  differing 
from  the  hideousness  of  the  carrion-feeders  on  the  one 

1  For  the  evidences  on  which  this  Spencer's  "Descriptive  Sociology," 
assertion  is  based,  too  numerous  for  under  heading  "  ^Esthetic  Senti- 
quotation    here,     see    Mr.    Herbert    ments,"jpassiwi. 


DIRECT  REACTION.  l8i 

hand,  and  the  cinereous  tone  of  the  carnivorous  birds  on 
the  other.  It  should  further  be  noted  that  the  owls  and 
bats  have  eyes  specially  modified  for  darkness,  by  the 
absence  of  the  cones,  which  we  have  seen  reason  to  conclude 
are  the  special  organs  of  colour-perception  ;  while  I  have 
alreadypointed  out  a  corresponding  structural  peculiarityin 
the  eyes  of  nocturnal  insects.  The  subterranean  mole  may 
perhaps  be  grouped  in  the  same  class. 

Third  in  this  connection  we  may  place  the  rapacious 
animals  generally.  Fishes  supply  us  with  the  shark  and 
pike.  Eeptiles  include  the  crocodiles  and  many  snakes. 
Birds  yield  instances  in  the  raptores  as  a  whole, — eagles, 
hawks,  falcons, — and  in  isolated  cases  such  as  the  shrike. 
Mammals  add  the  wolves,  bears,  and  insectivores.  The 
larger  cats,  however,  together  with  the  green  snakes,  must 
be  specially  excepted,  their  colouring,  as  we  shall  see 
hereafter,  being  protective  in  its  arrangement.  So,  of 
course,  must  be  the  animals  already  enumerated  among 
the  brilliant  class,  which  feed  upon  unusually  bright- 
coloured  prey. 

Other  cases  must  be  roughly  enumerated  in  a  single 
paragraph.  The  larger  marine  creatures  are  usually  dull : 
as  witness  whales,  porpoises,  walruses,  seals,  and  turtles. 
Fresh-water  animals  are  less  bright  than  the  smaller 
marine  and  terrestrial  fauna :  take  for  examples  river-fish, 
fresh-water  molluscs,  water-beetles,  otters,  voles,  coots, 
and  most  water-fowl.  The  mass  of  herbivores  are  quiet 
in  colouring,  though  often  pretty  according  to  our  deve- 
loped Aryan  taste.  Omnivorous  animals,  like  crows,  pigs, 
and  men,  are  not  usually  bright  in  their  tints.  Seed-eat- 
ing birds  have  mostly  grey  or  neutral  plumage.  Marine 
birds  are,  as  a  rule,  whitish  or  grey.  In  short,  the  im- 
mense majority  of  animals  v*^hich  do  not  feed  on  bright- 
coloured  food  are  of  plain  hues,  in  which  black  or  white 
predominates,  in  certain  muddy  mixtures,  with  very  little 
tinge  of  red,  yellow,  green,  or  blue,  and  with  no  spots, 
bands,  or  markings  of  pure  analytic  colours. 


i82  THE  COLOUR-SENSE. 

Lastly,  intermediate  between  the  two  classes  of  brilliant 
and  dull-coloured  animals,  we  get  what  may  be  called  the 
transitional  stage.  This  stage  shows  a  general  tendency 
to  pure  colours,  more  or  less  subdued  by  plainer  inter- 
mixtures ;  but  it  does  not  often  exhibit  perfectly  unmixed 
shades  of  crimson  or  azure.  It  is  represented  in  many 
insects,  especially  among  the  Lepidoptera  and  Coleoptera ; 
in  the  remaining  insessores  and  gallinaceous  birds;  in 
squirrels,  monkeys,  and  many  frugivorous  mammals ; 
and  in  numbers  of  snakes,  lizards,  and  amphibia.  Most 
of  these  may  be  said  to  hover  on  the  border  between 
bright  and  dingy  foodstuffs,  varying  from  flies,  grubs, 
slugs,  brownish  seeds,  and  small  grey  birds  or  mammals, 
to  gay  fruits,  butterflies,  birds'  eggs,  banded  snails,  bright 
little  reptiles,  and  birds  of  handsome  plumage.  As  a 
whole,  an  approximate  correspondence  can  be  traced  be- 
tween the  average  brilliancy  of  their  food  and  the  average 
brilliancy  of  their  own  colouring. 

If  all  these  be  mere  coincidences,  they  seem  to  me 
without  exception  the  most  extraordinary  coincidences 
ever  observed  in  nature.  But  even  a  list  such  as  this 
cannot  at  all  adequately  represent  the  real  state  of  the 
case.  I  may  therefore  be  pardoned  if  I  mention  that  the 
generalisation  here  so  insufficiently  enforced  has  been 
thrust  upon  me  by  three  separate  sets  of  observations. 
First  came  my  own  constant  observation,  that  within  the 
sphere  of  my  daily  experience,  in  walks  and  excursions, 
in  Europe,  North  America,  and  the  West  Indies,  I  found 
such  a  correspondence  between  bright  food  and  bright 
colouring,  or  dull  food  and  dull  colouring,  to  obtain  in  a 
vast  majority  of  cases.  Secondly,  visits  paid  for  the  pur- 
pose to  the  Zoological  Gardens,  the  British  and  other 
Museums,  and  the  various  aquariums,  in  order  to  satisfy 
myself  as  to  such  correspondence,  greatly  increased  my 
belief  in  its  truth.  After  examining  the  several  brilliant 
species,  I  made  inquiry  into  trustworthy  books  as  to  the 
nature  of  their  food,  and  I  almost  always  found  that  the 


DIRECT  RE  A  CTION.  1 83 

rough  generalisation  I  had  provisionally  framed  was  thus 
greatly  supported.  I  may  add,  too,  that  the  mass  of 
specimens,  as  seen  in  a  garden  or  a  cabinet,  produces  a 
far  more  vivid  impression  on  the  mind  than  is  possible 
from  the  mere  mention  of  isolated  names.  Thus  a  single 
instance,  like  that  of  the  peacock  or  the  flamingo,  has  great 
weight  under  ordinary  circumstances,  when  thought  of  in 
isolation ;  but  when  one  turns  from  a  case  full  of  the 
gallinaceous  birds  or  the  Avaders,  to  a  case  full  of  flower- 
haunting  humming-birds  or  fruit-eating  parrots,  the  dif- 
ference in  the  whole  averasje  of  instances  is  seen  to  be 
simply  infinite.  Accordingly,  I  would  strongly  urge  those 
who  wish  to  judge  of  my  theory  for  themselves,  to  make 
such  careful  comparisons  in  person,  at  some  one  of  our 
great  zoological  collections.  Thirdly  and  lastly,  during 
the  whole  course  of  my  reading  in  the  works  of  traveller- 
naturalists,  I  have  been  invariably  struck  by  the  same 
connection  of  food  and  hue.  Especially  has  this  connec- 
tion been  thrust  upon  me  once  more  by  Mr.  Wallace's 
admirable  work  on  "  Tropical  Nature,"  which  has  ap- 
peared since  the  present  volume  was  wholly  planned,  and 
in  great  part  written.  And  since  this  theory  is  the  part  of 
my  work  to  which  I  myself  attach  the  greatest  import- 
ance, and  for  which  I  expect  the  greatest  amount  of  hos- 
tile criticism,  I  venture  to  add  a  few  typical  passages 
from  my  notes,  gathered  from  those  works  which  have  so 
often  stood  us  in  good  stead  already,  and  jotted  down  in 
passing,  while  the  theory  was  still  vaguely  evolving  itself 
in  my  mind.  They  may  help  to  show  the  reader  the  style 
of  suggestion  which  comes  upon  one  from  every  side  with 
reference  to  this  subject. 

Of  the  fruit-pigeons.  Dr.  Jerdon  says,  "  These  pigeons 
are  of  very  large  size,  with  rich  and  metallic  colours ; "  ^ 
but  of  the  ground  pigeons  and  doves,  which  "feed  chiefly 
on  grains,"  he  observes,  "  they  are  of  more  dull  and  sombre 
colours."  ^     Mr.  Wallace  speaks  over  and  over  again  of 

1  Birds  of  ludia,  vol.  ii.  p.  455.  -  Ibid.,  p.  461. 


i84  THE  COLOUR-SENSE. 

similar  species,  such  as  the  lovely  little  fruit-eating 
Ftilinopus  pulchellus,  wliicli  "  is  of  a  beautiful  green 
colour  above,  with  a  forehead  of  the  richest  crimson, 
while  beneath  it  is  ashy  white  and  rich  yellow,  banded 
with  violet  red."  ^  Then  we  have  the  exquisite  Nicobar 
pigeon,  which  eats  "fallen  fruits,"  ^  the  "very  handsome 
fruit-pigeon  "  {Carjpophaga  concinna),  which  lives  on  nut- 
megs,^ and  the  "pretty  little  flower-pecker"  {Prionochilus 
aureolmibatiis),  whose  name  sufficiently  declares  its  golden 
markings.  Once  more,  Scissirostrum  Pagei  belongs  to  a 
family  generally  dull,  but  has  yellow  bill  and  feet,  and  a 
tail  of  "  vivid  crimson ; "  ^  and  on  inquiry,  we  see  that  it 
feeds  upon  fruit.  Soon  after,  we  read  concerning  a  flock 
of  the  "  fine  crimson  lory  {Eos  rubra),  a  parroquet  of  a  vivid 
crimson  colour,"  that  "  they  settled  down  upon  some 
flowering  tree,  on  the  nectar  of  which  lories  feed."  ^  Then 
again  we  have  the  "  large  green  barbets  {Megalcema  versi- 
color^), something  like  small  toucans,  .  .  .  whose  head  and 
neck  are  variegated  with  patches  of  the  most  vivid  blue 
and  crimson."*^  On  another  page  we  meet  with  a  lovely 
small  fruit-pigeon  (Ftilinojoiis  roseicollis),  "whose  entire 
head  and  neck  are  of  an  exquisite  rosy  pink  colour, 
contrasting  finely  with  its  otherwise  green  plumage."^  So, 
when  we  turn  to  Sir  Emerson  Tennant,  we  find  the  "  very 
beautiful  pigeon  "  Carpophaga  Torringtonice;^  the  exquisite 
flowers,  haunted  by  lovely  butterflies ;  and  the  magnificent 
bats  and  flying  squirrels,  which  feed  on  fruits.  Mr.  Bates 
similarly  tells  us  how  along  the  Amazons  the  butterflies 
were  found  in  great  brilliancy  on  the  flowery  parts,^  while 
amongst  them  flitted  "  fiery  red  "  dragon-flies  ;  how  "  from 
the  wild  fruit-trees  we  often  heard  the  shrill  yelping  of 
the  toucans  ; "  ^^  how  the  pretty  cigana  (Opisthoco77ms 
cristatics),  a  gallinaceous  bird,  eats  various  wild  fruits,  and 
how  at  one  place  on  the  river,  where  he  "  was  surprised 

1  Malay  Archipelago,  p.  528,  «  Ceylon,  p.  174. 

-  Ibid.,  p.  345.         2  Ibid.,  p.  291.  ^  Naturalist -on  the  Amazons,  pp. 

^  Ibid.,  p.  274.         ^  Ibid.,  p.  297.  20,  274,  et  ah 

6  Ibid.,  p.  28.          7  Ibid.,  p.  123.  io  Ibid. 5  p.  26. 


DIRECT  REACTION,  185 

at  tlie  number  and  variety  of  "brilliantly-coloured  butter- 
flies," lie  also  noticed  the  "  glossy-green  beak  and  rose- 
coloured  breast "  of  a  "  beautiful  bird  "  {Trogon  melanurus), 
and  the  "golden-bronze  and  steel  colours"  of  a  jacamar 
{Galbula  viridis),  which  fed  on  these  very  insects.^  On  the 
other  hand,  he  notes  how,  near  Santarem,  "  the  pastures 
are  destitute  of  flowers,  and  also  of  animal  life,  with  the 
exception  of  a  few  small  plain-coloured  birds."  ^  I  could 
multiply  these  instances  by  dozens,  but  I  only  select  the 
first  which  I  find  on  my  notes,  to  show  the  sort  of  evi- 
dence which  suggested  and  supported  the  theory,^  and  by 
observing  which  it  may  be  most  easily  confirmed.  Indeed, 
whenever  I  find  mention  of  any  brilliant  creature,  be  it 
Indian  Goliath-beetle,*  South- American  longicorn,^  scarlet- 
faced  monkey,^  gay-coloured  squirrel,'^  handsome  bats,^  or 
fairy  blue-birds,^  I  almost  always  notice,  either  coupled 
with  the  fact,  or  on  further  search,  that  the  animal  in 
question  feeds  upon  bright-coloured  food. 

It  will  perhaps  seem  like  pushing  the  conclusion  be- 
yond reasonable  limits  if  I  go  on  to  say,  that  in  some  cases 
one  may  even  possibly  detect  a  correspondence  in  actual 
tint  between  the  animal  and  its  food.  Yet  even  this 
appears  not  wholly  impossible.  Of  course  no  stress  can 
be  laid  on  some  two  dozen  or  so  of  such  instances,  some  of 
which  may  be  really  protective;  but  the  hint  is  worth 
throwing  out,  for  future  verification  or  disproof,  as  the 
case  may  be.^*^ 

^  Naturalist  on  the  Amazons,  p.  71.  •*  Hooker's  Himalayan  Journals,  ii. 

2  Ibid.,  p.  183.  98. 

5  It  is  worth  while,  perhaps,    to  ^  Bates,  w6i  sttp?*^,  p.  no. 

add    that  the    original   idea  of    the  ^  Ibid.,  p.  326. 

causal  connection  between  flowers  or  ^  Wallace,  Malay  Archipelago,  p. 

fruits  and  a  taste  for  colour,  which  I  123. 

first  worked  out  in  my  "  Physiological  ^  ^iv  Emerson    Tennant,    Ceylon, 

Esthetics,"  and   afterwards   in  this  p.  135. 

volume,    was   set    up    in    my   mind  ^  Jerdon,   Birds  of   India,  vol.   ii. 

while  watching  the  humming-birds,  p.  105. 

tropical  robins,    butterflies,    beetles,  ^^  I  had  collected  a  few  cases,  but 

and  lizards,  together  with  the  bios-  omit    them,    as    being   hitherto    in- 

soms,  berries,  and  capsicums,  in  my  suflicient. 
own  garden  in  Jamaica. 


1 86  THE  COLOUR-SENSE. 

And  now  tliat  we  have  completed  this  part  of  our 
inquiry,  let  us  once  more  return  to  Mr.  Wallace's 
objection  against  sexual  selection,  from  the  root  upward. 
When  we  were  considering  its  applicability  to  insects,  I 
pointed  out  that  the  "  theory  of  typical  colours "  really 
suffices  to  cover  the  whole  difficulty ;  and  the  same  argu- 
ment will  apply  to  vertebrates ;  for  if  recognisability  is 
a  requisite  of  the  typical  colouring,  it  may  well  happen 
that  those  species  which  feed  on  brilliant  objects,  being 
always  on  the  look-out  for  patches  of  colour,  will  be 
mutually  attracted  to  one  another ;  and  the  taste  thus  set 
up  and  strengthened  from  generation  to  generation  may 
become  an  additional  cause  for  differentiating  the  nascent 
species  from  others  of  different  habits.  As  the  taste  for 
brilliancy  and  the  frugivorous  mode  of  life  will  go  hand 
in  hand  with  one  another,  it  will  naturally  happen  that 
some  variety  of  colour  will  become  the  recognised  dif- 
ferentia of  the  particular  species,  whereby  its  members 
mutually  know  their  own  fellows  from  all  other  kinds. 
And  at  the  same  time,  inasmuch  as  all  species  of  flower- 
feeders  and  fruit-eaters  are  not  coloured  alike,  and  have 
not  the  same  ornamental  adjuncts,  I  fail  to  see  the  force 
of  Mr.  Wallace's  argument  that  all  individuals  seem  to 
pair  off  in  the  long  run ;  for  the  cesthetically- endowed 
individuals  would  pair  off  with  one  another,  while  the 
sesthetically-deficient  would  be  left  for  their  likes ;  and 
the  difference  thus  initiated,  correlated  as  it  must  neces- 
sarily be  with  other  peculiarities  of  taste  and  habit,  would 
become  in  turn  the  starting-point  for  a  fresh  differen- 
tiation. Indeed,  if  I  may  say  so  without  presumption 
concerning  so  great  a  naturalist,  Mr.  Wallace  seems  to  me 
here  to  have  fixed  his  eyes  rather  upon  the  loroclud,  the 
made  species,  than  upon  the  'process,  the  species-making.^ 

Moreover,  it  is  noteworthy  that  among  these  same 
brilliant  creatures,  which  owe  their  colours  ultimately  to 

^  See  especially  "Tropical  Nature/'  p.  206. 


DIRECT  RE  A  CTION.  i  Sy 

tlieir  briglit-hued  food,  we  find  the  greatest  profusion  of 
other  apparently  esthetic  and  sexual  ornaments.  The 
butterflies,  besides  their  colours,  are  remarkable  for  their 
queer  tails  and  other  appendages,  as  well  as  for  those 
allurements  of  scent  which  F.  Mtiller  has  pointed  out. 
The  beautiful  fishes  are  likewise  the  species  in  which 
stranc^e  excrescences  occur.  The  lizards  have  an  immense 
number  of  ornamental  devices,  like  pouches,  knobs,  a.nd 
horns.  The  humming-birds  and  sun-birds  are  distinguished 
by  their  ruffs,  crests,  lappets,  and  tail-feathers.  The 
parrots  and  birds  -  of  -  paradise  affect  similar  tricks  of 
plumage ;  which  are  also  found  in  the  hoopoes  and  many 
of  the  semi-brilliant  class.  The  handsome  gallinaceous 
birds  have  combs  and  wattles.  And  while  we  find  few 
such  ornamental  modifications  among  the  lower  mammalia, 
it  is  a  fact  pregnant  with  import  that  the  frugivorous  and 
arboreal  rodents  or  quadrumana  repeat  the  very  same 
peculiarities  of  crests,  tufts,  and  beards  which  are  so 
common  amongst  the  similarly-environed  forest  birds. 
Any  one  who  w^ill  take  the  trouble  to  look  through  the 
immense  collection  of  instances  in  Mr.  Darwin's  "De- 
scent of  Man,"  will  see  at  a  glance  that  the  most  brilliant 
tribes  are  also,  on  the  whole,  the  most  ornamented. 

On  the  other  hand,  one  may  hazard  the  rough  genera- 
lisation, that  the  animals  which  appeal  to  their  mates  by 
the  sense  of  hearing  are  not  those  which  appeal  by  the 
sense  of  colour.  The  stridulating  insects  and  the  singing 
birds  are  usually  plain  in  their  external  appearance.  It 
might  seem  as  though  the  habits  of  some  races  had  led 
them  to  attach  more  importance  to  sounds,  while  the 
habits  of  others  led  them  to  attach  more  to  colour.  In 
any  case,  we  may  be  quite  certain  that  no  such  taste  is 
fortuitous  and  isolated.  It  must  bear  some  definite 
relation  to  the  general  mode  of  life  throughout  the  race. 

One  more  question  remains.  Mr.  Wallace  observes 
with  great  truth  that  colour  may  be  regarded  as  a  normal 
product  of  organisation,  whose  presence  in  animals  does 


i88  THE  COLOUR-SENSE. 

not  need  to  "be  explained  so  mncli  as  its  absence.  But 
the  difficulty  at  once  crops  up — what  colour  ?  I  have  not 
space  fully  to  follow  up  this  ultimate  problem ;  but  we 
may  find  room  for  a  few  brief  suggestions. 

Almost  all  the  ornamental  appendages  of  animals  are 
modifications  of  the  skin  or  its  equivalent.  They  are 
found  most  frequently  and  strikingly  in  the  male  sex : 
and  they  are  most  conspicuous  during  the  breeding 
season.  Whatever  we  may  think  of  their  functions,  we 
must  agree  that  they  are,  on  the  whole,  products  of  high 
vitality.  They  represent  part  of  the  excess  of  nutriment 
over  expenditure.^ 

But  these  dermal  adjuncts  do  not  probably  take  away 
anything  from  the  effective  energies  of  the  organism.  As 
Mr.  Lowne  well  puts  it,  in  his  able  and  suggestive  work 
on  "  The  Philosophy  of  Evolution,"  the  formation  of  pig- 
ments and  like  matters  is  apparently  due  to  the  waste- 
products  of  the  other  organs.  "  The  dermal  appendages 
of  reptiles  and  the  feathers  of.  birds,  rich  in  pigment  and 
nitrogen,  are  probably  entirely  excrementitious  to  the 
other  tissues,  and,  without  doubt,  depend  in  great  part  for 
their  origin  on  the  solid  nature  of  the  excretion  of  the 
kidneys.  Birds  especially,  leading  a  very  active  life, 
excrete  material  rich  in  nitrogen  ;  and  the  feathers,  which 
are  shed  periodically,  enable  them  to  throw  off  that  ele- 
ment without  overtaxing  their  renal  organs."  And  again, 
"  A  given  pabulum  being  supplied,  certain  essential  struc- 
tures are  nourished,  and  the  residue  is  economised  in  the 
production  or  modification  of  other  parts,  often  giving  rise 
to  ornamental  appendages  or  bright  colours ;  whilst  the 
action  of  the  same  principle  correlates  the  modifications 
of  different  organs  or  parts  with  each  other."  2 

Hence  we  can  understand  why  the  more  active  and 
energetic  sex  should  possess  a  greater  number  of  highly 

1  Tropical  Nature,  p.  194.  Nutrition,  in   which  these  passages 

2  The  Philosophy  of  Evolution,  occur,  should  be  consulted  with  re- 
p.  75.     The  whole  of  the  chapter  on    ference  to  this  interesting  question. 


DIRECT  RE  A  CTION.  1 89 

developed  dermal  adjuncts,  and  should  often  display  much 
brighter  colours  than  the  females.  We  can  also  see  why 
these  integumentary  modifications  should  be  largest  and 
most  expanded  in  the  most  active  races,  such  as  butter- 
flies, birds,  flying-lizards,  and  arboreal  mammals ;  while 
conversely,  the  possession  of  these  very  organs,  in  the  case 
of  flying  animals  at  least,  is  itself  a  cause  of  their  in- 
creased locomotive  power.  Here  we  notice  a  remarkable 
instance  of  that  close  interaction  between  structure  and 
function  which  has  been  pointed  out  by  Mr.  Herbert 
Spencer, — the  function  first  developing  the  structure,  and 
each  increment  of  structure  permitting  increased  func- 
tion, which  once  more  becomes  in  turn  the  parent  of 
further  structural  modifications. 

But  we  do  not  yet  see  why  the  pigments  which  are 
deposited  in  the  dead  processes  of  the  skin,  should  possess 
one  colour  rather  than  another.  The  answer  to  this  ques- 
tion must  ultimately  depend  upon  the  habits  and  needs  of 
each  species.  Where  protective  colouring  proved  most 
useful  to  the  race,  it  would  be  acquired,  as  Mr.  Wallace 
has  well  pointed  out,  among  the  infinite  possible  varieties 
of  these  very  changeful  substances  ;  but  where  attractive 
hues  were  of  greater  advantage,  they  would  be  retained 
by  sexual  selection.  Mr.  Wallace  has  shown  why  ^pig- 
mcnt  should  be  developed  in  the  feathers  of  birds  and  the 
scales  of  butterflies ;  but  it  does  not  seem  to  me  that  he 
has  sufficiently  shown  why  one  pigment  rather  than  an- 
other should  be  developed.  The  black  colouring  of  the 
crow,  and  the  dusky  wings  of  owls  and  moths,  are  just 
as  much  products  of  that  integumentary  modification  on 
which  he  lays  so  mucli  stress,  as  are  the  bright  hues  of 
butterflies  or  the  plumage  of  parrots.  In  fact,  it  seems 
to  me  that  Mr.  AVallace  does  not  sufiiciently  distinguish 
between  pigment  and  bright  pigment. 

On  the  whole,  therefore,  while  fully  recognising  the 
value  of  Mr.  Wallace's  arguments  with  regard  to  the 
origin  of  pigments,  the  relation  of  ornament  to  activity. 


I90  THE  COLOUR-SENSE. 

the  protective  use  of  subdued  colour  in  certain  cases  to 
one  or  other  sex,  and  so  forth,  I  am  still  inclined  to  think 
that  the  general  coincidence  between  bright  food  and 
bright  colour  noticed  above,  does  really  warrant  a  belief 
in  such  a  simple  form  of  sexual  selection  as  that  here 
advocated.  Especially  am  I  inclined  to  suppose  that 
differences  of  taste  thus  originated  may  themselves  be 
active  differentiating  agents  for  the  production  of  new 
species  with  correlated  habits. 

A  few  further  suc^erestions  and  observations  of  a  (i^eneral 
character  may  here  be  added,  merely  as  hints  for  those 
who  wish  to  pursue  the  subject  independently. 

The  brightest  colouration  and  most  developed  orna- 
mental adjuncts  seem  to  be  confined  to  very  small  and 
active  animals,  such  as  butterflies,  beetles,  humming- 
birds, siin-birds,  and  flying-lizards.  Those  of  the  some- 
what larger  creatures,  parrots,  toucans,  fishes,  snakes,  and 
greater  reptiles  or  amphibia,  are,  on  the  whole,  not  quite 
so  brilliant  or  so  largely  developed ;  and  the  activity  of 
these  species  is  less  than  that  of  the  preceding  group. 
On  the  other  hand,  the  larojest  animals  of  each  sjreat  divi- 
sion,  among  vertebrates  at  least,  show  a  decided  tendency 
toward  very  dull  and  inconspicuous  hues;  take  as  ex- 
amples the  sharks,  sturgeons,  sun-fish,  tunny,  and  cod; 
the  oriaantic  salamander ;  the  crocodiles,  turtles,  and  cjreat 
snakes ;  the  ostriches,  emus,  eagles,  condors,  storks, 
swans,  and  penguins;  the  whales,  walruses,  elephants, 
hippopotami,  rhinoceroses,  gorillas,  bears,  buffaloes,  and 
elks.  These  are  mostly  slow  and  inactive  animals,  and 
they  are  also  little  distinguished  for  expanded  epidermal 
modifications.  Indeed,  it  may  be  said,  roughly  speaking, 
that  all  very  large  birds  or  mammals  show  more  or  less 
tendency  to  lose  or  minimise  their  feathers  or  hair. 

Those  larger  animals  which,  like  the  mandrill,  the  casso- 
wary, and  the  king- vulture,  display  brilliant  colouring, 
have  it  disposed  in  small  patches  on  a  particular  portion 
of  the  body,  not  over  its  whole  surface. 


DIRECT  REACTION.  191 

Flying  animals  seem  to  show  special  sestlietic  tastes. 
At  least,  they  are  largely  provided  with  apparent  sexual 
allurements.  Such  are  the  colours  of  birds,  flying-lizards, 
and  butterflies;  the  perfumes  of  some  Lepidoptera;  the 
stridulating  organs  of  insects  and  the  song  of  birds ;  and 
the  frills,  ruffs,  crests,  lappets,  or  tails  of  birds  and  butter- 
flies. Of  course,  the  origin  of  these  may  be  largely 
accounted  for  by  the  causes  which  Mr.  Wallace  assigns ; 
but  their  selection  and  persistence  seems  to  imply  an 
unusual  aesthetic  sensibility.  It  is  among  birds  alone,  too, 
that  we  find  clear  evidence  of  sesthetic  feelings,  as  with 
the  magpies  and  bower  birds.  Now,  is  it  not  possible 
that  the  comparative  security  which  each  flying  race 
obtained  on  its  first  development,  permitted  the  various 
species  to  indulge  their  taste  to  a  greater  degree  than 
would  have  been  the  case  with  terrestrial  creatures.^ 
Would  not  flying  creatures  be  more  likely  to  notice  and 
follow  the  attraction  of  such  a  sense-stimulation  than 
sluggish  terrestrial  animals  ?  And  might  not  the  intro- 
duction of  predatory  species  at  a  later  date,  capable  of 
preying  on  these  classes,  afterwards  modify  the  coloura- 
tion or  other  sexual  allurement  according  to  varying 
circumstances  ?  For  example,  may  not  the  growth  of 
insect-eating  birds  have  affected  butterflies  in  various 
ways,  so  as  to  preserve  those  with  protective  or  warning 
colours,  while  yet  leaving  many  traces  of  the  primitive 
sexual  colouration  ?  or  may  not  the  presence  or  absence 
of  hawks  and  birds  of  prey  have  determined  the  develop- 
ment of  song  or  colour  respectively  as  an  allurement  in 
each  species  of  bird  ?  Does  not  the  abundance  of  coloured 
animals  in  certain  isolated  lands,  lying  close  to  great  con- 
tinents, point  toward  the  conclusion,  that  where  special 
immunity  from  enemies  exists,  the  aesthetic  fancy  can  be 
more  implicitly  followed  ?     And  may  not  Mr.  Wallace's 

1  "The  most  conspicuous  pigeons,     have  the  fewest  enemies." — Wallace, 
whether  by  colour  or  by  their  crests,     Tropical  Nature,  p.  loj. 
are  all  found  in  countries  where  they 


192  THE  COLOUR-SENSE. 

own  remarks  upon  the  humming-birds  of  Juan  Fernandez 
possibly  bear  the  same  construction  ? 

A  similar  hint  may  be  thrown  out  with  regard  to  fish, 
which  bear  somewhat  the  same  relation  to  the  other 
inhabitants  of  the  ocean  as  flying  creatures  bear  to  the 
terrestrial  animals.  Indeed,  the  analogy  between  the  fins 
of  a  gurnard  and  the  wings  of  a  butterfly  must  have  been 
forced  upon  any  one  who  has  seen  those  exquisite  fish  in 
an  aquarium.  Again,  the  whole  group  of  higher  arboreal 
mammals  have  some  considerable  likeness  to  birds  and 
the  other  winged  animals  in  the  activity  of  their  move- 
ments, and  the  comparative  security  of  their  elevated 
position,  while  their  tendency  to  produce  such  forms  as 
the  flying  squirrels,  the  anomalurus,  the  galeopithecus, 
and  the  bats,  shows  how  close  the  functional  and  adaptive 
resemblance  may  sometimes  become.^  Now,  we  have 
already  seen  that  these  arboreal  animals  are  on  the  whole 
much  more  brightly  coloured  than  other  mammals,  and 
we  have  also  noted  their  tendency  to  develop  hairy 
appendages,  such  as  beards,  ruffs,  and  top-knots.  More- 
over, some  of  them  are  also  distinguished  for  their  loud 
and  piercing  cries  (produced  in  the  case  of  the  howlers  by 
a  special  organ),  which  may  be  compared  with  the  song  of 
birds,  and  the  presumably  sexual  noises  given  out  by  some 
other  creatures. 

Here,  too,  we  see  a  striking  analogy  between  the 
development  of  the  sense  of  sight  in  general  and  of  the 
colour-sense.  For  eyes,  as  we  observed  in  Chapter  iii.,  are 
most  developed  in  the  most  locomotive  races ;  and  the 
colour-sense,  the  highest  mode  of  sight,  seems  to  be  most 
highly  developed  only  in  exceptionally  locomotive  races. 
It  would  appear  natural  that  only  very  mobile  animals 
could  derive  any  special  advantage  from  the  indications 
afforded  by  colour,  and  hence  we  may  account   for  the 

1  The  flying-squirrels  are  \x\  all  other  flying  mammals  are  nocturnal 
cases  "remarkable  for  the  vivacity  that  they  may  be  safely  left  out  of 
of  their  colouring."     So  many  of  the     the  account. 


DIRECT  RE  A  CTION.  1 93 

special  share  which  flying  insects  and  birds  have  borne  in 
the  production  of  bright-hued  flowers  and  fruits,  as  well 
as  for  the  frequent  brilliancy  of  their  own  colouration. 

Once  more,  it  is  worth  noting  that  the  hair  of  mammals 
seems  very  little  adapted  for  the  display  of  brilliant  and 
pure  pigments.  The  best  that  can  be  said  of  the  hues 
produced  is  that  they  are  bluish,  rufous,  or  white,  never 
that  they  are  scarlet,  purple,  golden,  or  bright  blue.  The 
only  cases  in  which  mammals  present  really  brilliant 
colouring  are  those  like  the  mandrill  and  certain  other 
monkeys,  where  the  pigment  is  displayed  beneath  patches 
of  bare  skin,  not  in  the  hair  or  other  epidermal  modifica- 
tion. 

After  these  remarks  it  is  hardly  necessary  for  me  to  add 
that  I  attach  full  weight  to  Mr.  Wallace's  general  prin- 
ciples with  regard  to  the  importance  of  activity  and  of 
extended  tegumentary  surfaces  as  a  groundwork  for  the 
production  of  colour  or  ornamental  adjuncts.  But  I 
regard  sexual  selection,  in  the  modified  sense  already 
noted,  as  the  agency  by  which  the  particular  colours  and 
ornaments  have  been  chosen  from  the  whole  possible 
number,  and  fixed  in  the  typical  specific  mould. 

Finally,  it  may  be  well  to  point  out  that  a  certain 
analogy  seems  to  exist  between  the  commonest  animal 
pigments,  and  those  of  fruits  and  flowers.  Some  of  the 
colours  of  animals  fade  after  death,  whence  we  may  con- 
clude that  the  substances  of  which  they  are  composed 
remain  in  a  state  of  comparative  chemical  instability. 
But  most  of  the  colours  here  treated  of  remain  permanently 
after  death,  as  maybe  seen  in  the  case  of  stuffed  birds  and 
preserved  insects.  Accordingly,  these  bodies  may  be  con- 
sidered with  great  probability  as  comparatively  stable  in 
chemical  composition,  and  as  little  affected  by  the  danger 
of  oxidisation.  So  we  may  perhaps  guess  that  they  are 
themselves  oxidation  products  whose  affinities  are  nearly 
saturated.  If  so,  they  might  fall  ultimately  under  the 
same   category    with    the   colouring  matter   of    flowers, 

N 


194  THE  COLOUR-SENSE. 

fruits,  fading  leaves,  and  other  bright-hued  vegetal  pro- 
ducts. 

The  reader  will  doubtless  object  that  this  chapter  is  far 
from  being  conclusive.  I  am  well  aware  of  its  deficiencies 
in  this  respect,  and  shall  feel  fully  satisfied  if  it  only  prove 
suggestive. 


(     195    ) 


CHAPTER  X. 

THE   INDIRECT   REACTION   OF  THE  COLOUR-SENSE 
UPON  THE  ANIMAL  INTEGUMENTS. 

In  the  last  chapter  we  dealt  with  those  cases  in  which 
the  colour-sense  of  animals  directly  reacts  upon  the 
species  themselves  which  possess  it,  by  causing  the  more 
brilliantly-coloured  among  them  to  be  specially  favoured 
as  parents  of  future  generations.  In  the  present  chapter 
we  must  examine  that  other  class  of  cases  in  which  the 
colour-sense  of  one  species  indirectly  reacts  upon  the 
appearance  of  other  species,  by  causing  all  those  in- 
dividuals which  present  certain  tints  or  spots  to  be 
destroyed,  and  only  sparing  those  which  present  certain 
other  tints  or  spots.  In  other  words,  the  last  chapter 
dealt  with  sexual  selection;  the  present  chapter  deals 
with  natural  selection.  In  the  first  case  certain  special 
hues  are  favoured  and,  therefore,  perpetuated;  in  the 
second  case  certain  special  hues  are  disadvantageous  and, 
therefore,  weeded  out.  Hence  the  action  of  the  former 
cause  is  direct,  the  action  of  the  latter  indirect.  Sexual 
selection  actively  chooses  the  beautiful,  natural  selection 
passively  permits  the  fittest  to  survive. 

Many  of  the  cases  which  fall  under  the  present  head 
have  already  been  cited  elsewhere  as  proofs  of  the  exist- 
ence of  a  colour-sense  in  insects  or  vertebrates.  Never- 
theless, we  may  once  more  recapitulate  them  here,  partly 
for  the  sake  of  formal  completeness,  but  partly  also  to 
exhibit  their  mutual  relations  in  a  new  and  more  syste- 
matic light.      We   shall  thus   be   enabled  with  greater 


196  THE  COLOUR-SENSE. 

clearness  to  perceive  how  strong  is  the  cumulative  evi- 
dence which  they  afford  for  the  general  diffusion  of  a 
colour-sense  throughout  the  animal  world.  At  the  same 
time,  as  this  part  of  the  subject  has  ere  now  been  fully 
investigated  by  Mr.  Darwin,  Mr.  Wallace,  and  numerous 
other  well-known  naturalists,  I  shall  only  attempt  to  give 
a  very  brief  reasoned  resume  of  their  labours,  without 
references  or  details ;  referring  those  readers  who  wish  for 
fuller  information  on  the  point  to  the  original  works  from 
which  my  selection  is  made. 

The  colours  produced  (or  rather  spared)  by  natural 
selection  fall  under  two  groups,  the  Imitative  and  the 
Prohibitive. 

By  imitative  colours  we  imply  those  which  resemble 
the  hues  of  some  other  body  in  such  a  manner  as  to 
insure  protection  or  some  other  benefit  for  the  species 
which  possesses  them.  They  may  be  useful  for  either  of 
two  purposes, — to  escape  the  notice  of  enemies,  or  to 
deceive  prey.  In  the  first  case,  they  enable  the  animal 
to  avoid  being  itself  devoured ;  in  the  second  case,  they 
enable  it  to  devour  others  more  easily,  and  so  to  secure 
a  larger  amount  of  food  than  less  deceptively-coloured 
compeers.  In  the  former  instance,  we  must  suppose  that 
the  majority  of  the  original  species  which  did  not  possess 
the  imitative  colouring  have  been  discovered  and  devoured 
by  enemies  endowed  with  a  colour-sense,  while  those 
w^hich  did  possess  the  imitative  colouring  have  continually 
survived.  In  the  second  instance,  we  must  suppose  that 
the  individuals  which  had  no  imitative  colouring  have 
failed  to  secure  sufi6.cient  food,  through  betraying  their 
presence  too  readily  to  their  prey,  while  those  which  had 
such  colouring  have  successfully  deceived  their  quarry, 
and  so  continually  survived.  We  might  compare  the 
first  case  to  that  of  a  man  who  disguises  himself  in  order 
to  escape  the  observation  of  his  enemies ;  and  the  second 
case  to  that  of  a  man  who  hides  himself  under  boughs 
and  leaves  to  get  a  nearer  shot  at  game.     Practically, 


INDIRECT  RE  A  CTION.  1 97 

however,  it  is  often  hard  to  say  for  which  of  these  two 
purposes  a  particular  colour  has  been  developed;  and 
often  the  same  colouring  must  enable  the  animal  both  to 
deceive  its  enemies  and  to  escape  the  observation  of  its 
prey.  We  shall  not,  therefore,  attempt  in  the  sequel  to 
distinguish  between  them. 

One  large  class  of  imitative  colours  consists  of  a  general 
resemblance  to  the  whole  surrounding  environment.  Of 
this  we  have  cases  in  the  soles  and  other  flat-fish  which 
exactly  imitate  the  colour  and  speckled  appearance  of  the 
sand  on  which  they  lie — so  much  so  that  even  a  careful 
human  observer  is  often  deceived  at  a  distance  of  a  few 
feet.  Other  instances  are  those  of  the  birds,  reptiles,  and 
insects  of  Sahara,  all  of  which,  as  Canon  Tristram  observes, 
copy  closely  the  grey  hue  of  the  desert  around  them. 
Arctic  animals  are  almost  universally  white.  The  fishes 
and  Crustacea  which  live  among  the  sargasso  weed  have 
a  general  yellow  tint  which  renders  them  indistinguishable 
from  the  surrounding  masses  of  algse.  Large  marine 
animals,  as  Mr.  Darwin  points  out,  have  their  backs  dark 
and  their  bellies  whitish,  which  exactly  corresponds  to 
the  general  distribution  of  light  and  shade,  as  a  spectator 
looks  up  or  down  in  the  water.  Forestine  birds  and 
reptiles  have  ordinarily  a  ground-tint  of  green ;  and  small 
green  snakes  and  lizards  are  commonly  found  among  grass 
or  low  herbacje.  Geckos  are  marbled  like  the  walls  and 
rocks  on  which  they  run.  Some  sea-side  butterflies  have 
sand-coloured  wings.  Aphides  and  many  leaf-eating  cater- 
pillars are  bright  green  in  hue.  Other  instances  are  too 
numerous  for  insertion  here.  It  is  worth  notice,  however, 
that  we  find  the  general  tendency  to  imitative  colouring, 
in  accordance  with  the  whole  environment,  most  strongly 
displayed  where  the  environment  is  most  uniform  in  its 
hues — as  in  Sahara,  the  Arctic  snows,  the  sargasso  sea, 
or  the  sands  of  the  sea-bottom ;  because,  in  such  circum- 
stances, any  variation  of  tint  would  be  especially  notice- 
able.    Where  the  general  distribution  of  colour  is  most 


198  THE  COLOUR-SENSE. 

varied,  as  in  tropical  forests,  we  find  the  greatest  variety 
of  animal  colours ;  while  the  imitative  devices  are  usually- 
far  more  specialised,  so  as  to  resemble  some  particular 
object  in  the  environment,  not  the  prevailing  hue  of  the 
environment  as  a  whole. 

In  a  second  class  of  cases  the  resemblance,  though  still 
general,  shows  some  more  specialised  features  than  those 
noted  above.  Thus,  many  caterpillars  have  spots  which 
mimic  the  distribution  of  light  and  shade  among  the  leaves 
on  which  they  feed ;  and  Sir  John  Lubbock  refers  to  a 
like  cause  the  colouration  of  those  great  cats  which,  like 
the  leopard  and  jaguar,  live  among  trees.^  Similarly,  the 
same  naturalist  points  out  that  the  large  grass-frequenting 
caterpillars  have  longitudinal  lines,  corresponding  with 
those  of  the  herbage  around ;  while  "  those  which  live  on 
large-veined  leaves  have  oblique  lines,  like  the  oblique 
ribs  of  the  leaves."  The  jungle  cats,  too,  such  as  the 
tiger,  have  perpendicular  stripes,  "rendering  them  very 
difficult  to  see  among  the  brown  grass  which  they 
frequent ;  "  while  "  the  ground  cats,  such  as  the  lion  and 
puma,"  falling,  of  course,  under  our  previous  class,  "  are 
brownish  or  sand-colour,  like  the  open  places  they  in- 
habit." Here,  as  before,  only  a  few  typical  instances  can 
be  quoted,  out  of  many  hundreds  collected  by  various 
careful  observers. 

A  very  specialised  form  of  this  adaptation  to  parti- 
coloured environments  is  found  amongst  those  animals 
which,  like  the  chameleon,  and  the  chameleon-shrimp, 
possess  the  power  of  altering  their  colour,  in  accordance 
with  the  surface  upon  which  they  rest.  But  in  this  case 
it  is  remarkable,  as  Mr.  Wallace  observes,  that  only  such 
colours  can  be  produced  as  occur  normally  in  the  natural 
environment  of  the  particular  species. 

A  third  class  of  cases  with  imitative  colouring  proceeds 

1  See  his  interesting  Glasgow  lecture,  "  On  certain  Relations  between 
Plants  and  Insects." 


INDIRECT  RE  A  CTION.  1 99 

from  general  to  special  resemblances.  Here  we  may 
place  all  the  leaf-insects,  stick-insects,  and  other  creatures 
which  present  close  similarities  to  various  surrounding 
organic  bodies.  A  sufficient  number  of  these  have  been 
already  mentioned  to  avoid  the  necessity  for  repetition 
at  present. 

A  special  case  of  this  third  class  is  shown  in  the  well- 
known  phenomena  of  mimicry,  with  which  ]\Ir.  Bates  and 
Mr.  Wallace  have  made  us  familiar.  These,  too,  have 
before  received  ample  attention,  and  need  not  longer 
detain  us  now.  With  them  we  may  close  our  first  divi- 
sion of  Imitative  Colours. 

The  second  division,  that  of  Prohibitive  Colours,  em- 
braces those  cases  where  a  colour  acts  as  a  warning  of  some 
noxious  or  disagreeable  quality  in  its  possessor.  These 
colours  are  usually  very  conspicuous,  as  it  must  be  sup- 
posed that  they  court  attention,  and  so  prove  protective 
to  the  species.  Among  them  may  be  noticed  the  bright- 
coloured  but  nauseous  caterpillars  and  butterflies,  numerous 
inedible  reptiles  and  amphibia  (such  as  Mr.  Belt's  Nicara- 
guan  frog  already  quoted),  several  birds  of  pugnacious 
habits,  and  perhaps  some  beetles  and  dragon-flies.  Mr. 
E.  N.  Moseley  believes  that  the  colour  of  many  marine 
organisms  are  prohibitive,  and  act  as  warnings  to  hungry 
passers-by.  For  my  own  part,  however,  I  must  confess 
that,  when  I  consider  the  universality  of  colour  as  a  means 
of  attraction,  I  am  almost  as  much  inclined  to  doubt  the 
reality  of  these  explanations  as  Mr.  Wallace  is  inclined 
to  doubt  the  reality  of  sexual  selection. 

To  sum  up,  we  may  conclude  that  the  whole  colouration 
of  the  organic  world  is,  in  the  rough,  perfectly  explicable 
upon  the  hypothesis  that  the  higher  animals  generally 
possess  a  colour-sense  essentially  identical  with  our  own ; 
while  it  is  absolutely  inexplicable  if  we  suppose  that  they 
do  not  possess  such  a  colour-sense.  The  inference  is 
almost  irresistible,  that  this  hypothesis  is  true.  Our 
cumulative  proof  has  now  been  completed.     We  have  seen 


2CO  THE  COLOUR-SENSE. 

that  flowers,  fruits,  insects,  birds,  and  mammals,  all  show 
lis  just  the  colouration  which  we  should  naturally  expect 
if  we  believed  all  the  more  developed  animals  to  see 
colours  as  we  see  them.  We  have  also  observed  that 
many  of  them  do  undoubtedly  possess  such  powers  in  a 
manner  essentially  similar  to  ourselves.  Our  hypothesis 
is  thus  a  hypothesis  w^hich  explains  all  the  facts  ;  the 
cause  which  it  postulates  is  a  xera  causa,  a  cause  other- 
wise known  to  be  real  and  sufficient  for  the  production  of 
the  facts ;  and  so  far  as  many  of  the  cases  are  concerned, 
it  is  not  a  hypothesis  at  all,  but  a  known  and  ascertained 
certainty.  The  grounds  for  believing  in  a  common  and 
identical  colour-sense  amongst  all  the  higher  animals  are 
accordingly  seen  to  be  practically  irresistible. 

Note. — At  the  conclusion  of  the  present  portion  of  my  work  which 
deals  with  the  colour-sense  in  lower  animals,  it  may  be  well  to  p'bint 
out  what  are  the  chief  instances  of  organic  colouration  which  the 
theories  here  adopted  leave  yet  unexplained.  They  may  be  briefly 
summed  up  under  three  heads.  The  first  includes  the  radiate 
animals,  and  such  other  marine  creatures  as  the  sea-slugs  and  some 
of  the  lower  articulates.  It  is  possible  that  the  colours  in  these 
cases  may  be  purely  adventitious,  depending  entirely,  hke  the  green 
of  leaves,  on  the  chemical  constitution  of  the  pigmentary  substance, 
and  subserving  no  special  function  as  colours.  This  is  particularly 
likely  in  the  case  of  deep-sea  organisms,  living  at  a  depth  where 
little  or  no  light  can  ever  penetrate.  (See  Sir  "Wyville  Thomson's 
''Depths  of  the  Sea,"  passim,  and  especially  pp.  465,  466.)  Never- 
theless, animals  found  under  such  circumstances  occasionally  possess 
very  large  and  striking  eyes  (see,  for  examj)le,  the  figure  of  Cystosoma 
JS'epturii  in  Sir  W.  Thomson's  "  Voyage  of  the  Challenffer"  p.  130), 
so  that  the  colours  may  perhaps  be  protective.  Upon  this  difficult 
subject  the  reader  may  consult  Mr.  Moseley's  interesting  papers, 
where  the  colours  of  deep-sea  organisms  are  explained  as  survivals 
of  a  habit  originally  acquired  for  protective  purposes  in  shoal  water. 
The  second  class  includes  the  shells  of  mollusca.  At  present,  I  see 
no  other  explanation  of  their  colours  save  that  they  are  purely 
adventitious  ;  but  this  last  refuge  must  only  be  regarded  as  pro- 
visional, since  fresh  facts  or  suggestions  are  continually  coming  to 
light,  which  enable  us  to  discover  some  functional  reason  for  what 
at  first  sight  appeared  purely  accidental.     The  third  class  includes 


INDIRECT  RE  A  CTION.  201 

the  eggs  of  birds.  And  here  I  am  disposed  to  allege  as  a  possible 
explanation  that  the  colouration  may  act  as  a  supplementary  allure- 
ment to  the  instinct  of  incubation,  just  as  sexual  colours  act  as  a 
supplementary  allurement  to  the  instinct  of  reproduction.  This 
theory  will  seem  less  far-fetched  when  we  recollect  the  fact  that  the 
eggs  of  reptiles,  usually  abandoned  by  the  mother,  are  generally 
quite  dingy  in  their  coverings,  while  those  of  birds,  forming  objects 
of  such  great  parental  solicitude,  are  almost  always  more  or  less 
beautiful  in  their  hues.  And  if  we  put  these  indications  beside  the 
other  marks  of  eesthetic  feeling  in  birds — their  song,  colour,  dermal 
adjuncts,  ornamental  nests,  bowers,  and  occasional  habit  of  abstract- 
ing brilliant  objects — the  theory  certainly  gains  in  verisimilitude. 
On  the  other  hand,  it  must  always  be  remembered  that  the  occur- 
rence of  colour  never  really  demands  an  explanation  in  organic 
bodies,  any  more  than  it  does  in  the  ruby,  the  sapphire,  or  the 
emerald. 

For  further  details  upon  the  colouration  of  animals  the  reader 
must  be  referred  to  Mr.  Wallace's  admirable  work  on  "Tropical 
Nature." 


(      202      ) 


CHAPTER  XL 

THE  COLOUR-SENSE  IN   MAN. 

"We  have  now  completed  our  survey  of  the  colour- sense  in 
animals  generally,  and  we  come  to  consider  its  manifesta- 
tion in  man. 

If  the  conclusion  to  which  we  have  been  led  in  our 
previous  investigation  be  correct,  if  all  the  higher  animals, 
and  amongst  them  the  quadrumana,  be  endowed  with  a 
perception  of  colour  substantially  the  same  as  our  own, 
then  it  will  naturally  follow  that  man,  the  descendant  of 
an  advanced  quadrumanous  type,  must  have  possessed  the 
same  faculty  from  the  very  earliest  period  of  his  separate 
history.  The  colour-sense  must  be  a  common  property  of 
all  mankind,  in  every  country,  and  in  every  age. 

Here,  however,  we  are  confronted  by  the  adverse  theory 
of  Mr.  Gladstone  and  Dr.  Hugo  Magnus,  who  endeavour 
to  convince  us,  on  the  contrary,  that  the  sense  of  colour  is 
quite  a  late  and  post-historical  acquisition  of  the  human 
race.  From  philological  evidence  in  the  Yedas,  in  the 
Hebrew  scriptures,  and  in  the  Homeric  poems,  they  con- 
clude that  some  three  thousand  years  ago  the  foremost 
tribes  of  the  Semitic  and  Aryan  races  were  incapable  of 
distinguishing  between  red,  blue,  green,  and  yellow. 
Starting  from  such  an  imaginary  primitive  state,  they 
trace  up  the  developm.ent  of  the  colour-sense  through  the 
succeeding  ages,  marking  out  four  principal  stages  in  the 
growth  of  the  perception.  All  this  startling  theory  they 
set  forth  on  purely  philological  grounds.     I  shall  briefly 


THE  COLOUR-SENSE  IN  MAN,  203 

give  the  main  points  of  their  hypothesis,  almost  in  the 
very  words  of  Mr.  Gladstone.^ 

The  starting-point  is  an  absolute  blindness  to  colour  in 
the  primitive  man.  Thence,  in  the  progressive  education 
of  the  organ,  three  chief  colours  have  been  successively 
disclosed  to  it,  and  have  appeared  in  the  order  of  their 
greater  or  less  refrangibility — red,  green,  violet.^  The 
first  stage  attained  is  that  at  which  the  eye  becomes  able 
to  distinguish  between  red  and  black.  Eed  comes  first 
into  our  perceptions,  because  it  is  the  most  luminous  of 
the  colours ;  but,  says  Geiger,  in  the  Rigveda  white  and 
red  are  hardly  severed.  In  the  next  stage  of  the  develop- 
ment, the  sense  of  colour  becomes  completely  distinct 
from  the  sense  of  light.  Both  red  and  yellow  with  their 
shades  (including  orange)  are  now  clearly  discerned.  To 
this  stage  Magnus  refers  the  Homeric  poems,  in  which  red 
and  yellow  colours  are  set  forth,  while  no  mention  is  made 
(according  to  these  authorities)  of  green  or  blue.  The 
characteristic  of  the  third  stage  is  the  recognition  of 
colours  which  in  point  of  luminousness  belong  to  neither 
extreme,  but  are  in  a  mean,  namely,  green  with  its  varieties. 
Finally,  in  the  fourth  stage  of  the  development,  we  find 
an  acquaintance  with  blue  begins  to  emerge.  This  is  a 
stage  not  even  now  reached  universally ;  for  example,  in 
Burma  (it  is  alleged  by  Bastian)  a  striking  confusion 
between  blue  and  green  is  a  perfectly  common  phenome- 
non, and  a  like  confusion  is  not  unusual  among  ourselves 
by  candle  light.^ 

Of  course,  the  first  point  which  strikes  an  evolutionist 
on  being   confronted  with  this  elaborate  theory  is  the 

^  I  have  to  thank  Mr.  Gladstone  for  ^  Extracted  almost  literally  from  Mr. 

his  courtesy  in  forwarding  me  a  copy  Gladstone's  article  on  "The  Colour- 

of  his  pamphlet,  and  also  for  kindly  Sense"    in    the    "Nineteenth    Cen- 

calling  ray  attention  to    some   con-  tury,"  for  October  1877.     References 

troversial  articles  which  appeared  on  to  the  works  of  Geiger  and  Magnus, 

this  subject  in  Kosmos.  as  also  to  the  various  controversial 

2 1  copy  Mr.  Gladstone's  words,  but  papers  which  they  have  called  forth, 

he   evidently  means  in  the    inverse  will  be  found  in  full  on  a  previous 

order  of  their  refrangibility.  page. 


204  THE  COLOUR-SENSE. 

utter  inadequacy  of  the  time  assigned  for  the  origin  of 
such  strong  and  fundamentally  differentiated  sensations 
as  those  of  colour.  Had  Dr.  Magnus  said  three  million, 
or  even  thirty  million  years,  the  evolutionist  could  have 
hesitated  on  the  score  of  insufficient  elbow-room;  but 
when  our  author  suggests  three  thousand  years  for  the 
growth  of  a  radically  separate  set  of  sentient  organs,  our 
incredulity  becomes  absolute  and  irrevocable.  It  would 
be  useless,  however,  to  oppose  the  doctrine  on  such  purely 
a  'priori  grounds,  only  efficient  for  those  who  accept  the 
general  hypothesis  of  evolution:  and  we  must  therefore 
seek  to  discover  w^hat  a  'posteriori  arguments  can  be  urged 
on  the  other  side,  against  the  philological  evidence  of  Mr. 
Gladstone  and  Dr.  Magnus. 

There  are  two  kinds  of  proof  for  the  universality  of  the 
colour-sense  in  man  which  we  may  offer  in  opposition. 
The  first  method  consists  in  showing  that  all  human  races 
at  the  present  day,  including  the  lowest  savages,  do 
actually  possess  just  the  same  sense  of  colour  as  our- 
selves :  whence  we  may  argue  with  considerable  proba- 
bility that  they  derive  that  sense  from  a  common  ancestor, 
and  that  the  Homeric  Akhaians  were  not  likely  to  be 
destitute  of  perceptions  possessed  by  the  Bushmen,  the 
Australians,  and  the  hill-tribes  of  India.  The  second 
method  consists  in  showing  that  works  of  art  and  other 
remains  of  the  early  historical  races  or  of  pre-historic 
man  yield  evidence  that  the  colour-sense  was  fully 
developed  long  before  the  epoch  of  the  Iliad  or  the  Book 
of  Genesis.  Both  these  methods  of  proof  we  shall  employ 
here. 

In  order  to  discover  what  was  the  present  state  of 
colour-perception  amongst  existing  savage  races,  I  had 
recourse  to  two  plans.  In  the  first  place,  I  consulted  a 
large  number  of  works  by  travellers  and  others  respecting 
modern  savages,  and  extracted  all  passages  which  bore 
upon  the  question  at  issue.  And  in  the  second  place,  I 
supplemented  the  information   thus   obtained  by  direct 


THE  COLOUR-SENSE  IN  MAN.  205 

inquiries  upon  the  subject,  addressed  to  missionaries, 
g-;overnment  officials,  and  other  persons  working  amongst 
the  most  uncivilised  races.  I  printed  a  circular  letter, 
which  I  forwarded  to  various  parts  of  the  world,  requesting 
iiumbered  answers  to  the  following  questions : — 
I"  (i.)  What  is  the  race  to  whom  your  answers  refer  ? 

(2.)  How  many  colours  can  they  distinguish  ? 

(3.)  Can  they  distinguish  between  blue  and  green  ? 

(4.)  Can  they  distinguish  between  blue  and  violet  ? 

(5.)  Can  they  distinguish  any  mixed  or  intermediate 
shades,  such  as  mauve,  lilac,  orange,  and  purple  ? 

(6.)  For  how  many  colours  have  they  names  in  their 
language  ? 

(7.)  Have  they  separate  names  for  green  and  blue  ? 

(8.)  Have  they  separate  names  for  blue  and  violet  ? 

(9.)  How  many  colours  do  they  discriminate  in  the 
rainbow  ? 
\  (10.)  What    pigments    do    they   employ   in  personal 
'  decoration  or  in  ornament  ? 

(11.)  Have  they  a  separate  name  for  each  pigment  ? 

(12.)  Have   they  separate   names   for   any  colour  for 
which  they  have  no  pigment  ? " 

To  these  questions  I  received  a  large  number  of 
courteous  answers,  from  Europe,  Asia,  Africa,  America, 
and  the  Pacific  Islands ;  and  I  may  as  well  say  at  once 
that  they  bore  out  in  every  case  the  supposition  that  the 
colour-sense  is,  as  a  whole,  absolutely  identical  through- 
out all  branches  of  the  human  race.  As  it  would  be 
tedious,  however,  to  print  all  the  answers  in  full,  as 
numbered,  in  a  tabular  form,  I  shall  give  the  whole 
evidence  together,  remarking  in  each  case  whether  my 
information  was  derived  from  books  or  fmrn  a  corres- 
pondent. 

I  shall  also  premise  that,  lest  there  should  be  any 
suspicion  that  I  myself  was  deficient  in  colour-perception, 
I  rigorously  tested  my  own  powers  with  all  the  objective 
experiments  I  could  hear  of  or  devise,  including  Dr.  Stil- 


2o6  THE  COLOUR-SENSE. 


ling's  Tables  for  the  Examination  of  the  Colour- Sense, 
and  many  like  careful  tests.     The  result  proved  beyond^, 
doubt  that  my  eyes  were  perfectly  normal,  and  possessed^ 
at  least  quite  the  full  average  faculties  of   colour  dis- 
crimination. 

Probably  nobody  will  deny  that  the  ordinary  European 
nations,  and  the  Chinese,  Japanese,  and  Hindus  in  Asia, 
have  colour-perceptions  identical  with  our  own.  The 
mere  inspection  of  their  works  of  art,  and  especially  of 
their  imitative  paintings,  clearly  shows  that  they  perceive 
and  represent  external  objects  of  the  same  hue  as  our- 
selves. I  shall  therefore  pass  them  over  without  further" 
proof,  and  proceed  to  examine  the  various  lower  races, 
beginning  with  the  most  advanced  among  them,  and. 
ending  with  the  most  degraded  of  all. 

The  North  American  Indians,  as  I  can  testify  from 
personal  experience,  make  use  of  pigments  for  the"  three 
so-called  primary  colours,  and  also  for  green,  orange,  and 
purple.  My  father,  Mr.  J.  A.  Allen  of  Kingston,  Ontario , 
who  kindly  undertook  to  distribute  my  circulars  in 
America,  thus  describes  some  Indian  art  products  of  the 
unsophisticated  north-western  tribes.  ''While  I  write,) 
I  have  before  me  some  leggings  and  mocassins,  made  by| 
Indians  of  the  far  west — so  far  off  as  to  be  hardly  reached 
by  the  last  outskirts  of  our  civilisation.  In  these,  the 
lines  of  colour  are  never  confused — never  fail  to  corres- 
pond, or  run  into  one  another.  The  leggings  have  orna- 
ments in  white,  dark  blue  and  pale  blue,  dark  green  and 
pale  green,  and  yellow,  on  a  scarlet  ground  with  a  black 
edge.  There  are  also  on  the  mocassins  pale  blue,  purple, 
brown,  green,  pink,  and "  solf erino,  on  a  buff  ground,  with 
a  strip  of  scarlet  binding.  The  pattern  is  strictly  sym- 
metrical: each  colour  being  introduced  at  exactly  the 
same  angle  or  portion  of  the  pattern  throughout — not 
a  confused  mass  of  colours.  They  were  brought  .  . .  from 
the  Chippewa  Indians,  750  miles  north-west  of  Kingston." 
Mr.  P.  B.  Bell  answers  my  questions  with  regard  to  the 


THE  COLOUR-SENSE  IN  MAN.  207 

Ojibways  in  similar  language.  They  can  clearly  distin- 
guish between  blue  and  green,  and  also  between  blue  and 
violet,  though  they  have  no  distinctive  name  for  the  latter 
colour.  They  have,  however,  no  less  than  seven  different 
colour-names,  including  separate  words  for  green  and 
blue.  Other  correspondents  mention  like  facts  of  other 
tribes.  In  all,  the  power  of  discrimination  seems  quite 
equal  to  our  own,  though  the  nomenclature  generally 
extends  only  to  the  four  or  five  most  markedly  different 
colours — a  point  to  which  we  shall  return  in  a  later 
chapter. 

The  evidence  with  regard  to  the  historical  races  of 
North  and  South  America  is  equally  strong.  The  ancient 
Mexicans  were  famed  for  their  mosaic  of  feather  work, 
and  their  subtle  taste  in  colour  is  praised  by  several  com- 
petent Spanish  authorities.^  I  have  satisfied  myself,  by 
personal  observation  of  Mexican  works  of  art,  that  they 
clearly  distinguished  all  the  colours  mentioned  by  Mr. 
Gladstone.  The  Yucatanese  "  painted  their  bodies  red,"^ 
but  the  children  whom  they  offered  as  victims  to  their 
gods  were  anointed  blue.  Stephens  says  that  their  prin- 
cipal colours  were  red,  green,  yellow,  and  blue;^  while 
Catherwood  praises  their  harmonious  blending  of  various 
hues.  The  Chibchas,  we  are  frequently  told,  had  a  special 
taste  for  emeralds  and  other  green  stones,  which  is  scarcely 
consistent  with  the  idea  that  they  could  not  see  their 
colour.*  The  Peruvians,  according  to  Garcilasso,  were 
"very  fond  of  vermilion  red;"^  but  they  too  had  a  par- 
ticular fancy  for  turquoises,  emeralds,  and  crystals.^  It 
is  specially  noticed  that  Atahuallpa  wore  a  collar  of  large 
emeralds.     Mr.  Clements  K.  Markham  informs  me  that 

^  Clavigero,  vii.  48,  57,  et  alii  alibi,  when  possible,  from  other  sources,  or 

Bee  also  Helps,  iv.  69.     In  this  and  from  direct  inspection  of  remains, 
many  other  cases  I  have  availed  my-         ^  Landa,  Kelacion,  §  20. 
self  of  the  large  and  careful  collection        ^  Yucatan,  vol.  i.,  p.  205. 
of  instances  in  Mr.  Herbert  Spencer's        ^  P.  Simon,  p.  256  ;  Uricoechea,  p. 

"DescriptiveSociology,"  which,  how-  52  ;  Piedrahita,  v.  4,  &c. 
ever,   I  have  greatly  supplemented,        *  Garcilasso,  viii.  25. 

6  Ibid.,  viii.  23. 


2o8  THE  COLOUR-SENSE. 

the  Peruvian  language  had  separate  words  for  green  and 
blue ;  and  in  one  of  his  published  works  he  mentions  that 
the  people  "knew  the  secret  of  fixing  the  dyes  of  all 
colours, — flesh-colour,  yellow,  grey,  blue,  green,  black." ^ 
Their  pottery  also  receives  high  commendation  as  "re- 
markable for  harmony  of  colour."  So  that,  on  the  whole, 
we  may  credit  all  the  semi-civilised  American  races,  not 
only  with  a  proper  colour-sense,  but  also  with  considerable 
artistic  sensibility. 

Even  of  the  wretched  Fuegians  I  find  it  noticed  that 
red  is  their  favourite  colour,^  and  that  they  paint  their 
faces  with  red,  black,  or  white. 

Passing  over  to  Africa,  we  meet  with  evidence  of  a 
similar  sort.  The  Eev.  A.  E.  M.  Wilshere  of  Bobbins 
Island,  Cape  of  Good  Hope,  obligingly  answered  my 
questions  with  regard  to  four  South  African  tribes, 
Korannas,  Hottentots,  Makatese,  and  Mozambiques.  In 
every  case,  he  found  by  personal  inquiry  that  all  recog- 
nised colours  were  discriminated  in  just  the  same  manner 
as  by  Europeans.  Every  one  of  these  tribes  can  dis- 
tinguish between  blue  and  green,  as  well  as  between  blue 
and  violet;  and  they  possess  names  for  six  separate 
colours,  including  green  and  blue,  but  not  violet ;  yet  as 
they  can  see  the  latter  colour,  the  deficiency  here  is  simply 
one  of  nomenclature.  In  one  case,  a  Mozambique  had  no 
native  word  for  purple,  which  is  wanting  in  his  own 
language,  but  had  learnt  the  name  in  Dutch,  and  applied 
it  correctly.  Mr.  Wilshere  is  of  opinion  that  the  Africans 
he  examined  could  discriminate  just  as  many  colours  in 
the  rainbow  as  he  could  himself. 

A  lady,  whose  name  I  have  no  authority  to  publish, 
gives  me  a  very  clear  account  of  the  Bushmen,  derived 
from  immediate  inquiry,  and  marked  by  a  careful  and 
conscientious  accuracy  which  could  not  sufficiently  be 
indicated  without   transcribing  her  letter  in  full.     The 

1  Markham's  Cieza,  p.  405. 


THE  COLOUR-SENSE  IN  MAN.  209 

members  of  tliis  race  can  undoubtedly  distinguish  red, 
yellow,  green,  blue,  violet,  purple,  and  orange.  Their 
colour  vocabulary  is  unusually  full;  for  besides  names 
for  the  common  primaries,  "  there  are  also  various  com- 
pound names,  where  the  names  of  two  colours  are  used 
together ;  as  well  as  further  names  for  at  least  five  (and 
probably  more)  shades  of  colour;  —  for  instance,  for 
light  purple,  for  lavender  and  grey,  for  stone-colour,  for 
brownish  green,  and  for  blue  green."  At  a  meeting  of 
the  Eoyal  Society  of  Edinburgh,  in  January  1878,  Bishop 
Cotterell,  formerly  of  Grahamstown,  gave  a  similar  account 
of  this  race,  whose  colour-perception  he  believed  to  be 
quite  as  acute  as  our  own.  Some  of  their  paintings, 
which  have  been  exhibited  in  this  country,  fully  bear  out 
the  truth  of  both  statements. 

With  regard  to  the  common  negro  types,  my  own 
observations  made  upon  West  Coast  Africans  in  Jamaica 
(not  born  in  the  West  Indies,  but  taken  from  Africa 
direct),  convinced  me  that  they  could  perfectly  discrimi- 
nate all  colours  as  well  as  myself.  The  ordinary  negro 
women  possess  the  same  abundant  vocabulary,  as  regards 
the  colours  used  in  dress,  which  distinguishes  their  sex  in 
Europe.  Nevertheless,  to  make  assurance  doubly  sure, 
I  append  a  few  references  to  their  pigments  and  works 
of  art  in  a  native  state.  The  Congo  people  paint  them- 
selves with  red  ochre,i  and  the  Mandingoes  dye  cloth  blue 
with  indigo.  The  huts  on  the  lower  Niger  are  stained 
blue  and  white.^  The  inland  negroes  dye  their  hair 
bright  blue.  Indeed,  throughout  all  Central,  Western, 
and  Northern  Africa,  where  indigo  exists,  it  appears  to 
form  a  favourite  pigment.  The  Ashantis  use  red,  blue, 
yellow,  and  green.^  The  Bushmen  paint  themselves  with 
red  ochre,*  while  among  the  favourite  beads  of  the  Bechu- 

1  Tuckey,  Expedition  to  the  Zaire,  '  Beecham,  Ashanti  and  Gold 
p.  103.  Coast,  p.  147. 

2  Allen  and  Thomson,   vol.    i.  'p.  ^  Barrow,  i.  288. 
320. 


210  THE  COLOUR-SENSE. 

anas,  Burchell  mentions  light  blue.^  Other  instances 
might  be  adduced  by  the  dozen ;  but  it  will  be  better 
simply  to  refer  the  reader  to  Mr.  Spencer's  great  collec- 
tion, or  to  any  manufacturer  of  trading  beads. 

The  Eev.  F.  A.  Gregory  of  Antananarivo  informs  me 
that  the  Malagasy  people  distinguish  accurately  between 
all  colours,  and  have  separate  names  for  no  less  than 
thirteen  hues. 

Among  the  hill  tribes  of  India,  colour-perception  seems 
to  exist  in  exactly  similar  perfection.  Mr.  Adarji  Jivanji, 
Deputy-Collector  at  Maldha,  ansv/ers  my  questions  with 
regard  to  the  Chondras,  Gamtas,  Dublas,  and  Bhils.  These 
aborigines  can  certainly  distinguish  between  blue,  green, 
and  violet,  though  not  possessing  separate  names  for  each. 
Other  observers  return  similar  answers  for  the  Nagas, 
Gonds,  and  like  lowest  races.  In  every  case,  discrimina- 
tion seems  perfect,  vocabulary  only  being  at  fault.  My 
friend.  Dr.  W.  W.  Hunter,  Director-General  of  Statistics 
for  India,  in  his  "  Comparative  Dictionary  of  the  Lan- 
guages of  India  and  High  Asia,"  gives  the  words  for 
green,  red,  and  black  in  107  Non-Aryan  dialects,  includ- 
ing those  of  the  Todas,  Khonds,  Uraons,  Kols,  Gonds, 
Santals,  Nagas,  Garos,  and  other  low-type  aborigines. '^ 
There  is  also  abundant  practical  evidence  that  these  races 
discriminate  blue,  which,  according  to  Mr.  Gladstone  and 
Dr.  Magnus,  represents  the  highest  stage  of  colour-percep- 
tion. The  Kukis  dye  cloth  with  indigo.^  The  Nagas 
wear  blue  kilts,*  and  cotton  dyed  w^ith  indigo,  as  well  as 
white  cloth,  wdth  red  and  blue  fringes.^  The  Todas 
embroider  their  mantles  with  blue  thread.^  The  Santals 
use  strips  of  red,  blue,  and   yellow  cloth.     The  Karen- 

1  Southern  Africa,  vol.  ii.  p.  569.  '  Stewart,  in  Journal  of  the  Asia- 

2  My  thanks  are  due  to  Dr.  Hunter  tic  Society  of  Bengal,  vol.  xxiv.  p. 
for   kindly   forwarding   my    circular     62,6. 

letters  to  various  Indian  civil  ser-  *  Grange,  Ibid.,  viii.  p.  469. 

vants,    amongst    the    least    civilised  5  ]bid.,  p.  613. 

tribes,  and  also  for  kindly  permitting  6  King,  Journal  of  the  Anthropo- 

me  to  use  for  reference  his  valuable  logical  Society,  July  1870,  p.  23. 
library  of  works  relating  to  India. 


THE  COL  0  UR-SENSE  IN  MAN.  2 1 1 

nees  of  Burma  wear  red  and  blue  clothing.l  Here,  again, 
only  the  necessary  limit  of  space  prevents  the  multiplica- 
tion of  instances,  but  many  hundreds  could  be  given  if 
required,  to  exactly  the  same  effect. 

With  regard  to   the  Pacific   Islanders,  my  fullest  in- 
formation comes  from  the  Eev.  S.  J.  Whitmee,  a  mis- 
sionary in  Samoa,  whose  name  is  already  well  known  to 
philologists  and  students  of  folk-lore,  as  that  of  a  careful 
and  strictly  scientific  observer.     Mr.  "Whitmee  considers 
that  the   Samoans   can    "  distinguish   all   the   prismatic 
colours,  and    many  of  the  mixed  shades."     They   have 
separate  names  for  blue  and  green,  and  others  for  the 
minor  modifications  of   these  hues.     They  have  also  a 
separate  name  for  violet.     They  discriminate  such  inter- 
mediate or  mixed  colours  as  mauve,  lilac,  orange,  and 
purple  ;  they  use  distinct  terms  for  varieties  of  red  (crim- 
son and  brick  red) ;  and  they  have  a  name  for  chocolate- 
brown.     On  the  whole,  their  nomenclature  seems  some- 
what awkward  and  confused,  but  their  perception  perfect : 
and    as   to  taste,   "  they  like   bright   colours,"   says  Mr. 
Whitmee,  "  such  as  mauve,  bright  blue,  purple,  magenta, 
&c. ;  but  they  do  not  mix  these  in  a  grotesque  manner  in 
their  dress  to  any  great  extent.  .  .  .  Large  showy  patterns 
in  prints,  &c.,  they  will  not  look  at.     Bright  red  is  not 
used   to  any  great   extent,  and  yellow  is  not  at  all  in 
favour."     The  Hawaiians   are  equally  discriminative  of 
colour  distinctions,  and  one  whom  I  had  the  opportunitv 
of  questioning  showed  quite  as  acute  sensibility  as  any 
European.     Mrs.  Bird   mentions  dresses  of  pure  white, 
crimson,   yellow,  orange,  scarlet,  blue,  or  light  green  as 
worn  by  the  women  ;  ^  and  throughout  her  book  she  bears 
constant   testimony  to  the   universal   feeling  for  colour 
harmony.     I   specially  note   that  she  mentions  the  use 
of  green  for  decorative  purposes  in  embroidery.^     Lord  G. 
Campbell  remarks  that  the  Admiralty  Islanders  who  came 

^  Fytche,  Burma  Past  and  Present.        ^  Hawaiian  Archipelago,  p.  21. 
i.  337«  ^  Ibid.,  p.  160. 


212  THE  COLOUR-SENSE. 

on  board  tlie  Challenger  to  be  painted  were  equally 
pleased  with  daubs  of  red  or  of  green  pigment.^  In  New 
Guinea,  blue  lines  are  employed  for  tattooing,^  and  the 
natives  paint  their  bodies  with  red,  yellow,  and  black.^ 
The  petticoats  worn  by  the  women  on  gala  days  are  dyed 
red  and  green,  with  intermediate  bands  of  straw-colour. 
The  New  Zealanders  stain  themselves  with  red  ochre ;  but 
I  find  ear-drops  of  green  jade  mentioned  among  their 
favourite  ornaments.*  Their  blue  tattoo  marks  are  too 
well  known  to  require  special  mention.  As  regards  the 
Malay  Archipelago  generally,  Mr.  Wallace's  vocabularies 
contain  words  for  black,  white,  red,  and  blue  in  thirty- 
three  Malayan  languages.  Mr.  W.  Gifibrd  Palgrave 
mentions  white,  yellow,  red,  green,  and  blue  among  the 
dyes  used  by  the  Philippine  Islanders.^  For  Australia,  I 
find  in  a  vocabulary  of  the  Wailwun  language  separate 
words  for  black,  red,  yellow,  green,  and  brown,^  and  several 
accompanying  lists  of  other  dialects,  collected  by  different 
authorities,  show  similar  results.  I  may  add  that  when- 
ever I  have  had  the  opportunity  of  consulting  intelligent 
travellers  upon  this  subject,  they  have  always  at  once 
given  their  opinion  that  the  savages  with  whom  they  were 
conversant  distinguished  all  colours  perfectly. 

Finally,  even  the  wretched  Andaman  Islanders,  pro- 
bably the  lowest  known  specimens  of  the  human  race, 
daub  their  faces  with  red  and  white.'^ 

Such  are  a  few  selected  instances  from  the  mass  of 
evidence  which  might  be  adduced  in  favour  of  the  belief 
that  all  existing  races  possess  a  fully-developed  colour- 
sense.  I  think  they  will  probably  suffice  to  show  the 
general  truth  of  our  proposition.     And  if  savages  so  low 

\  Log-Letters  from  the  Challenger,  ^  Journal  of   the   Anthroi^ological 

p.  282.  Infstitute,  vol,  vii.  No.  3,  p.  246. 

2  Voyage  of  the  i^a^i?esJ^a^•e,  p.  262.  7  m_  John,    "Transactions  of  the 

3  Earl's  Papuans,  p.  26.  Ethnological  Society,  New  Series,  v. 

4  Anga's  Australia  and  New  Zea-  45.  See  also  Colebrooke  in  "Asiatic 
land,  vol.  i.  p.  327.  Researches, "  iv.  390. 

^  ]\Ialay  Life   in   the   Philippines, 
"Cornhill  Magazine,  "Aug.  1878,  p.  157. 


THE  COLOUR-SENSE  IN  MAN  213 

as  some  of  tliese  actually  enjoy  sucli  high  powers  of  dis- 
crimination, can  we  consistently  deny  the  like  to  the  early 
Hebrews  and  Akhaians  ?  I  have  not  so  high  an  opinion 
as  Mr.  Gladstone  of  the  rude  Homeric  warriors  or  the 
tierce  conquerors  of  Lower  Syria,  but  at  least  I  cannot 
believe  that  they  were  less  advanced  in  simple  sensuous 
perceptions  than  the  naked  Todas  or  the  wild  half-human 
Andamanese. 

And  now  let  us  go  on  to  inquire  whether  we  cannot  find 
abundant  proofs  of  a  highly  evolved  colour-sense  long 
before  the  period  to  which  the  criticisms  of  Geiger  and 
Magnus  refer. 

First,  in  our  backward  view  we  will  take  the  case  of 
Nineveh.  Of  the  enamelled  bricks  dug  up  in  this  city 
Sir  A.  H.  Layard  says,  "  The  colors  {sic)  have  faded,  but 
were  probably  once  as  bright  as  the  enamels  of  Khorsabad. 
The  outlines  are  white,  and  the  ground  a  pale  blue  and 
olive  green.  The  only  other  color  used  is  a  dull 
yellow."^  In  many  of  these  cases  blue  figures  occur  on  a 
green  ground,  w^hich  clearly  shows  that  the  two  colours 
were  accurately  discriminated.  The  pigments  consist  of 
an  antimoniate  of  lead  for  the  yellow ;  an  oxide  of  tin  for 
the  white;  a  copper  for  the  blue;  and  a  sub-oxide  of 
copper  for  the  red.  Of  Babylonian  bricks  the  same 
authority  observes,  "  The  principal  colours  are  a  brilliant 
blue,  red,  a  deep  yellow,  white,  and  black."  ^  The  Eev. 
A.  H.  Sayce,  the  distinguished  Assyriologist,  writes  to 
nie  as  follows : — "  The  Assyrian  language  seems  to  have 
had  no  word  for '  green.'  Sometimes  *  green '  is  represented 
by  arlvii,  '  yellow,'  but  more  commonly  by  'saum  or  'sihmu 
'  blue'  (like  the  Welsh  glas).  But  the  enamelled  bricks 
show  that  both  the  colours  blue  and  green  were  known 
and  used."     An  inspection  of  the  existing  remains  in  the 

1  Nineveh  and  Babylon,  p.  166.  Monarchies,"   iii.  pp.  406,  407,  and 

2  For  an  account  of  Babylonian  Layard's  "Nineveh  and  Babylon," 
colours,   see    Eawlinson's   "Ancient    pp.  507,  672. 


214  THE  COLOUR-SENSE. 

Louvre  and  the  Britisli  Museum  will  sufficiently  prove  to 
the  most  sceptical  that  the  colour-sense  of  the  Assyrians 
was  essentially  identical  with  our  own. 

As  to  the  Egyptians,  proof  seems  almost  unnecessary ; 
3^et,  for  the  sake  of  formality,  it  must  be  given.  "  Their 
colours,"  says  Sir  Gardner  AVilkinson,  "were  principally 
blue,  red,  green,  black,  yellow,  and  white.  The  red  was 
an  earthy  bole ;  the  yellow  an  iron  ochre ;  the  green  was 
a  mixture  of  a  little  ochre  with  a  pulverulent  glass,  made 
by  vitrifying  the  oxides  of  copper  and  iron  with  sand  and 
soda ;  the  blue  was  a  glass  of  like  composition  vAtlioid  the 
ochreoiLS  addition ;  the  black  was  a  bone  or  ivory  black ; 
and  the  white  a  very  pure  chalk."  ^  Here  the  words 
which  I  have  italicised  clearly  prove  that  the  difference 
between  blue  and  green  was  perfectly  perceived,  and  that 
pigments  were  specially  prepared  to  show  the  two  colours. 
Again,  Sir  Gardner  observes,  "  With  the  Egyptians  the 
favourite  combination  of  colour  was  red,  blue,  and  green ; 
when  black  was  introduced,  yellow  was  added  to  har- 
monise with  it."  Nor  is  this  all ;  for  though  they  had 
few  mixed  colours,  yet  "  purple,  pink,  orange,  and  brown 
are  met  with."  A  modern  author,  speaking  of  their 
ceramic  art,  uses  lan^juac^e  of  even  a  more  decided  kind. 

'  do 

"  One  finds  in  the  rich  series  of  the  Louvre,"  says  Jac- 
quemart,  "pieces  with  white  glaze,  heightened  wdth 
patterns  incrusted  or  painted  in  black,  blue,  dark  violet, 
green,  and  even  red ;  the  green  and  the  copper  blue  blend 
with  cobalt  blue,  black,  brown,  violet  of  manganese,  white, 
and  yellow.  What  proves,  beside,  with  what  certainty 
the  potters  operated  these  combinations  is,  that  we  meet 
with  Egyptian  porcelains  where  the  diverse  tints  occupy 
very  confined  spaces,  and  contrast  strongly  the  one  with 
the  other;  a  blue  statuette  has  the  face  coloured  with 
golden  yellow ;  dark  blue  bracelets  bear  upon  their  sur- 
face hieroglyphics  in  sky  blue,  or  vice  versa!' ^     ''Here, 

1  Ancient  Egyptians,  ii.  292, 
-  History  of  the  Keramic  Art,  English  translation,  p.  16. 


THE  COLOUR-SENSE  IN  MAN.  215 

then,  is  complete  science,  consummate  experience,  and 
precision  of  execution." 

But  a  few  hours  spent  at  the  British  Museum,  especially 
amongst  the  mummy-cases,  will  do  more  to  convince  the 
reader  of  the  Egyptian  colour-sense  than  pages  of  quota- 
tion. Among  the  wall-paintings,  too,  I  would  call  parti- 
cular attention  to  those  numbered  170,  177,  180,  181, 
and  many  neighbouring  specimens  of  the  eighteenth  and 
nineteenth  dynasties. 

As  regards  the  date  of  these  coloured  remains,  I  made 
inquiries  of  Dr.  Birch,  who  kindly  informed  me  that  tlie 
system  of  colouring  culminated  under  the  two  dynasties 
abovementioned,  and  grew  gradually  debased  thence- 
forward. Accordingly,  the  finest  specimens  of  Egyptian 
colouration  are  far  anterior  to  the  earliest  conjectural 
date  ever  proposed  for  the  Homeric  poems. 

Can  w^e  go  still  further  back,  to  the  prehistoric  age,  and 
show  by  the  evidence  of  existing  remains  that  even  then 
man  possessed  a  developed  colour-perception  ?  I  believe 
that  we  can,  to  some  slight  extent  at  least. 

Of  course,  in  dealing  with  the  art-products  of  the  most 
primitive  period,  we  must  not  expect  to  find  such  un- 
mistakable proofs  as  those  of  pigments  and  paintings 
which  we  meet  with  in  Egypt  and  Assyria.  If  the  savage 
races  of  the  present  day  were  to  die  out  and  leave  no 
traces  but  those  of  their  scanty  implements,  we  could 
hardly  hope  to  discover  many  marks  of  their  now  un- 
deniable use  of  colour.  The  tattooing,  the  body-paints, 
the  strips  of  coloured  cloth,  the  flowers  and  feathers,  all 
would  be  lost  by  decay.  Even  the  rude  decorations  of 
the  pottery  would  probably  fade  by  long  exposure  to 
earth,  rain,  and  air.  The  only  remains  which  could 
convey  to  us  some  faint  idea  of  that  love  for  colour  which 
distinguishes  the  real  savage  w^ould  be  the  few  perma- 
nently-coloured implements  of  stone  or  metal.  I  was 
standing  with  a  friend  one  day  by  the  glass  cases  in  the 
Oxford  Museum  which  contain  the  modern  savage  uten- 


2i6  THE  COLOUR-SEXSE, 

sils,  when  lie  called  my  attention  to  a  stone  hatcliet  (I 
think  from  the  Admii^alty  Islands),  bound  to  its  wooden 
handle  by  a  coil  of  red  and  yellow  cord,  arranged  so  as  to 
form  a  pretty  pattern.  We  had  been  talking  upon  this 
very  subject,  and  he  rightly  pointed  out  at  once  that  if 
the  hatchet  were  buried  in  the  earth  for  a  very  short 
period,  the  red  and  yellow  cord  would  decay,  and  no 
mark  of  the  original  aesthetic  intention  would  be  left. 
Similarly,  if  we  did  not  learn  from  the  actual  words  of 
Csesar,  and  the  constant  allusions  of  the  Eoman  poets, 
that  the  ancient  Welsh  stained  their  bodies  blue,  we 
should  know  almost  nothing  about  their  sense  of  colour. 
The  conditions  under  which  we  find  prehistoric  remains — 
buried  in  barrows,  covered  up  in  alluvium,  sunk  in  lakes, 
or  hidden  in  the  damp  floor  of  caves — necessarily  preclude 
the  possibility  of  obtaining  any  very  definite  information 
on  this  head.  Still  the  evidence,  such  as  it  is,  distinctly 
favours  the  belief  in  a  normal  colour-sense  amongst  these 
most  primitive  men. 

To  begin  with  the  highest  stratum  of  the  prehistoric 
period,  we  may  put  in  the  evidence  of  Dr.  Schliemann, 
who  gives  plates  of  red  and  yellow  Mycenean  pottery, 
with  colours  distinctly  brilliant  and  fairly  well  demar- 
cated.^ It  is  true,  no  greens  or  blues  appear  upon  these 
vessels,  but  the  reason  for  this,  as  we  shall  hereafter  see, 
was  much  more  probably  due  to  the  lack  of  a  proper  pig- 
ment than  to  a  deficiency  of  the  colour-sense.  Among 
the  gems  of  Mycenae,  agate,  porphyry,  and  greenstone 
occur,  and  we  can  hardly  doubt  that  their  colour  was  their 
chief  recommendation  in  the  eyes  of  the  early  chieftains 
in  whose  graves  they  are  discovered.  Amber  and  lapis 
lazuli  are  also  found,  showing  a  probable  knowledge  of 
yellow  and  blu.e.  Indeed,  the  mere  fact  that  gold  and 
silver  vessels  are  used,  proves  a  certain  amount  of  colour 
perception,  for  gold  only  differs  from  silver  in  its  colour, 

1  Mycense   and   Tiryn?.-  plates   A,    B,  C,  and  D.      See  also    "Troy   and 
its  Kemains,"  p.  49. 


THE  COL 0  UR- SENSE  IN  MAN.  2 1 7 

and  could  not  be  discriminated  in  any  other  way,  except 
by  chemical  tests. 

But  that  some  at  least  of  the  Bronze  Acre  savajres 
possessed  a  taste  for  blue,  and  employed  it  in  their  arts, 
is  conclusively  shown  by  a  bracelet  from  the  Swiss  lake 
dwellings,  which  has  a  red  ground,  distinctly  and  prettily 
enamelled  with  yellow  and  blue  bands  in  a  regular 
pattern.i  Blue  and  white  glass  beads  also  form  part  of 
the  treasure  recovered  from  the  d6lris  of  these  primeval 
villages.^ 

Going  back  to  the  Stone  Age,  we  find  similar  evidence, 
though  of  a  scanty  sort.  "  Stones  remarkable  either  for 
their  colour  or  shape,"  says  Dr.  Evans,  "appear  at  all 
times  to  have  attracted  the  attention  of  mankind,  and 
frequently  to  have  served  as  personal  ornaments."^  Among 
the  ordinary  materials  of  stone  weapons  Damour  mentions, 
"  quartz,  agate,  Hint,  jasper,  obsidian,  fibrolite,  jade,  chloro- 
melanite,  amphibolite,  aphanite,  diorite,  saussurite,  and 
staurotide ; "  and  we  can  hardly  fail  to  notice  that  many 
of  these  minerals  are  remarkable  for  their  beauty  of 
colour.  "  In  the  Christy  collection,"  says  Dr.  Evans  else- 
where, "  is  a  hola  formed  of  a  polished  spherical  red  stone, 
mounted  in  such  a  manner  as  to  show  a  considerable 
portion  of  its  surface,  which  has  evidently  been  regarded 
as  too  handsome  to  be  entirely  concealed  by  the  leather."^ 
Canon  Greenwell  found  beads  of  bluish-green  glass  in 
barrows  in  Yv^iltshire.^  Amber  was  also  found  in  similar 
situations;  and  beads  of  rose-quartz,  belonging  to  the 
Stone  Age,  are  recorded  at  Argenteuil.*^  Pebbles,  selected 
apparently  for  their  beauty,  are  constant  accompaniments 
of  the  dead,  some  of  them  being  described  as  "sea- 
green,"  "pink,"  and  "red."''    How  far  back  in  time  these 

1  Desor  and  Favre,  Le  Bel  Age  du        ^  Ibid.,  p.  378. 
Brouze    Lacustre  en  Suisse,   p.    23,        ^  British  Barrows,  p.  55. 
luid  plate  iii.  fig.  15.  6  Evans,  uhi  supra,  p.  413. 

2  Ibid.,  p.  15,  and  plate  iii.  fig.  i.  7  ibid.,  p.  419. 
^  Ancient    Stone    Implements    of 

Great  Britain,  p.  422. 


2i8  THE  COLOUR-SENSE. 

deposits  may  reach  I  cannot  say ;  but  in  one  case  at  least, 
that  of  the  Dardanelles  remains,  I  find  it  distinctly  stated 
that  they  are  of  palaeolithic  age,  "  and  the  most  common 
material  is  red  or  other  coloured  jasper."^  The  Christy 
collection  also  includes  axes  from  Barbadoes  of  "green- 
stone, mottled  jade,  green  jasper,  and  a  hard  light  green 
slate."^  I  may  add  that  the  stone  implements  in  Dr. 
Schliemann's  Trojan  collection  at  South  Kensington  from 
all  depths,  though  much  begrimed  by  age,  show  traces  of 
deep  colour  in  many  different  shades.  The  most  conclu- 
sive of  all  proofs,  however,  is  the  occurrence  of  ochre  in 
barrows.^  And  Dr.  Eollestoue  informs  me  that  he  has 
constantly  found  lumps  of  ruddle,  doubtless  for  personal 
ornamentation,  laid  by  the  side  of  the  dead.  He  thinks 
the  general  character  of  prehistoric  remains  can  leave  no 
doubt  on  the  mind  of  an  expert  that  primitive  man 
possessed  a  considerable  perception  of  colour. 

Few  and  inconclusive  as  these  facts  undoubtedly  are, 
they  yet  afford  a  reasonable  presumption  in  favour  of  a 
colour-sense  in  the  earliest  members  of  the  human  race. 
However,  it  w411  not  be  necessary  to  base  any  part  of  our 
argument,  as  against  Mr.  Gladstone  and  Dr.  Magnus,  upon 
so  insecure  a  foundation.  We  may  rest  content  with  the 
cases  of  the  Egyptians  and  the  modern  savages,  having 
the  post-historic  theory  here  on  the  horns  of  a  dilemma 
which  it  cannot  easily  escape.  If,  on  the  one  hand,  we 
put  forward  only  the  case  of  Egypt,  it  might  be  answered 
tliat  the  development  of  a  colour-sense  is  a  question  of 
relative  culture,  not  of  mere  chronological  order ;  and  if, 
on  the  other  hand,  we  put  forward  only  the  case  of  modern 
savages,  it  might  be  answered  that  the  development  of  a 
colour-sense  is  a  question  of  chronological  order,  not  of 
relative  culture ;  but  if  we  put  forward  the  two  cases 
together,  it  will  hardly  be  possible  for  any  one  to  shirk 

^  "Wilson,  Prehistoric  Man,   vol.  i.        ^  Greenwell,    Eritish   Barrows,   p. 
p.  III.  ii8. 

-  Ibid.,  vol.  i.  p.  123. 


THE  COLOUR-SENSE  IN  MAN.  219 

the  first  difficulty  by  answering  ns  in  one  way,  and  then 
to  shirk  the  second  difficulty  by  answering  us  in  the  other. 
When  we  examine  the  extraneous  arguments  by  which 
the  theory  is  supported,  we  find  they  have  very  little  real 
weight.     Thus  it  has  been  suggested  that  colour-blindness 
may  be  a  survival  from  this  earliest  type  of  vision ;  but 
when  we  look  a  little  deeper  into  the  question  we  recollect 
that  the  commonest  form  of  colour-blindness  is  that  which 
cannot  discriminate  red  from  green — whereas  red  ought, 
according  to  the  theory,  to  be  the  most  universally  dis- 
criminable  of  all — while  it  is  yet  quite  able  to  discriminate 
green  from  blue.     Furthermore,  there  is  good  reason  for 
believing  that  colour-blindness  is  far  commoner  in  civilised 
communities  than  amongst  savage  tribes.     According  to 
M.  Favre,  no  less  than  3,000,000  persons  in  France  are 
afflicted  with  this  defect,  while  Stilling  places  the  propor- 
tion in  Western  Europe  generally  at  5  per  cent.^     On  the 
other  hand,  the  abnormality  appears  to  be  infrequent  or 
unknown  amongst  the  lower  races ;  so  that  it  must  be 
regarded  rather  as  a  disease  of  civilisation  than  as  a  sur- 
vival from  the  primitive  state.     Again,  Dr.  Magnus^  quotes 
Geiger's  remarks  about  the  dog  and  the  flower  to  prove 
that  quantitative  consciousness  of  intensity  has  nothing 
to  do  with  qualitative  consciousness  of  kind;  or,  as  Mr. 
Gladstone  puts  it,^  "  that  the  dog,  with  his  wonderful 
faculty  of   scent,  has  no  power  of  distinction   between 
smells  which  are  agreeable  and  smells  which  are  offensive." 
Eeally,  as  we  have  already  seen,  there  is  no  reason  under 
the  sun  why  a  dog  should  find  the  smell  of  flowers  affect 
him  distinctively  in  any  way ;  while  if  we  set  him  to  track 
a  scent,  crossed   and  recrossed  from  step   to  step  by  a 
hundred  varying  trails,  we  shall  see  that  he  does  possess 
a  qualitative  sensibility  of  the  very  highest  order.     Ac- 
cordingly the  supposed  analogy  breaks  down  immediately. 

1  stilling,  Priifung  des  Farbensin-        -  Geschiclitliche  Entwickelung  des 
nes,  p.  5.  Farbensinnes,  p.  3. 

2  The  Colour-Sense,  p.  3. 


220  THE  COLOUR-SENSE. 

Or,  once  more,  to  take  a  third  instance,  Mr.  Gladstone 
speaks  of  the  difficulty  experienced  in  distinguishing  blue 
from  green  by  candle-light  as  a  trace  of  the  undifferenti- 
ated stage ;  but  really  violet  is  quite  easily  discriminated 
under  such  circumstances,  while  it  ought,  if  the  theory  be 
true,  to  be  the  least  discriminable  of  all  colours ;  and  as  to 
the  confusion  itself,  it  is  in  fact  objective,  not  subjective, 
depending  upon  the  peculiar  constitution  of  certain  lights 
which  do  not  contain  all  the  prismatic  colours  in  the 
normal  proportions  of  sunlight.  One  miglit  almost  as 
well  argue  that  as  blue  Bengal  fires  make  everything  look 
blue,  therefore  blue  is  probably  the  original  colour  dis- 
criminated by  the  eye. 

Indeed,  the  whole  hypothesis  has  only  one  weak  set  of 
facts  to  support  it,  namely,  the  supposed  testimony  of 
language.  Setting  aside  for  the  present  the  possibility 
that  this  testimony  has  been  misinterpreted  (which  I  hope 
to  show  in  the  sequel),  it  must  at  least  be  granted  that  the 
negative  evidence  of  language  by  itself  forms  the  most 
untrustworthy  ground  for  such  a  superstructure,  especially 
if  contradicted  by  other  positive  proofs.  I  look  in  vain 
through  the  pages  of  Geiger,  of  Magnus,  and  of  Mr.  Glad- 
stone, for  any  indication  that  pictures,  sculpture,  pottery, 
or  other  art  products  have  been  taken  into  consideration 
at  all.  Every  one  of  these  students  seems  to  have  sat 
down  in  his  library,  consulting  the  frail  linguistic  authority 
of  the  Yedas,  the  Homeric  poems,  and  the  Hebrew  pro- 
phets ;  but  never  to  have  tested  the  truth  of  the  philolo- 
gical conclusion  by  reference  to  museums  and  art  collec- 
tions, or  even  to  the  works  of  antiquaries  and  explorers. 
Dr.  Magnus  argues  a  priori  as  to  what  the  sensations  of 
the  savage  must  he  like ;  but  he  has  taken  no  pains  to 
inform  himself,  either  by  observation,  inquiry,  or  reading, 
what  they  actually  are  like.  I  cannot  help  believing  that 
a  little  more  care  and  a  little  more  extended  search  would 
have  led  him  to  abandon  his  theory,  based  as  it  is  upon 
the  shifting  sands  of  half-forgotten  languages.     It  may 


THE  COLOUR-SENSE  IN  MAN.  221 

seem  hardly  worth  while  to  combat  an  opinion  apparently 
so  harmless ;  but  every  error  is  necessarily  productive  of 
evil,  because  it  retards  the  progress  of  discovery;  and  so 
I  shall  not  apologise  for  the  time  which  I  have  taken  in 
endeavouring  to  overthrow  this  misleading  doctrine. 

Leaving  aside,  then,  for  the  present  the  doubtful  evidence 
of  language,  what  is  the  general  conclusion  to  which  we 
are  forced  ?  Man  is  the  descendant  of  an  arboreal  quad- 
rumanous  animal,  of  frugivorous  habits,  who  shared  the 
common  vertebrate  faculty  of  colour-perception,  and  the 
common  fruo-ivorous  taste  for  brifrht  hues.  From  the 
earliest  period  of  his  separate  development  he  exhibited 
the  ancestral  liking  by  his  fondness  for  red,  green,  and 
yellow  pebbles ;  for  ochreous  earths  and  other  pigments ; 
and  probably  for  flowers,  feathers,  and  like  natural  objects. 
Long  before  the  dawn  of  history  we  find  him  surrounding 
himself  with  these  aesthetic  adjuncts ;  and  wherever  we 
see  him  still  in  the  same  early  stage  of  development,  wc 
meet  with  the  self-same  coloured  ornaments.  The  earliest 
historical  nations  discriminated  and  employed  in  decora- 
tion every  chief  prismatic  hue,  at  an  age  long  anterior  to 
that  in  which  we  are  asked  to  believe  that  the  colour- 
sense  was  unknown.  Throughout  all  historical  time,  in 
Egypt,  Assyria,  China,  India,  Peru,  Mexico,  and  Western 
Europe,  colour  has  been  distinguished  and  used  just  as  it 
is  at  the  present  day.  And  over  the  whole  known  world, 
among  the  most  civilised  and  the  most  savage  races  alike, 
the  perception  of  colour  now  appears  to  all  competent 
observers  exactly  identical. 

Before  we  go  on  to  examine  the  philological  question, 
we  shall  find  it  convenient  to  trace  the  aesthetic  purposes 
to  which  colour  has  been  applied ;  and  we  shall  then  be  in 
a  position  to  judge  why  and  how  far  the  vocabulary  of  the 
early  Akhaians  and  Hebrews  was  deficient  in  terms  ex- 
pressive of  distinctive  hues. 


(     22: 


CHAPTER   XII. 

THE  ESTHETIC  VALUE   OF   COLOUR. 

We  have  seen  already  that  pleasure  results  from  the  un- 
impeded activity  of  a  fully-nurtured  structure,  in  imme- 
diate connection  with  a  sentient  centre,  when  not  exces- 
sive in  amount,  nor  surpassing  the  limits  of  easy  repair.^ 
/Esthetic  pleasure  results  from  such  activity  when  directed 
upon  objects  remote  from  actual  life-preserving  function.^ 
Accordingly,  the  sesthetjc^pleasure  of  cglonr  i.s  Xhe 
pleasure  felt  in  its  immediate  appreheusiuu  by  the  mind, 
apart  from  any  idea  of  advantage  to  be  gained,  as,  for 
instance,  from  the  acquisition  of  food.  Even  the  lower 
animals  show  some  signs  of  a  love  of  colour  for  its  own 
sake,  as  in  the  oft-quoted  cases  of  the  bower-birds  and 
many  monkeys.  More  often,  however,  their  appreciation 
of  colour  is  bound  up  with  the  essential  acts  of  feeding 
and  reproduction,  exhibiting  itself  only  in  its  secondary 
effects  by  the  genesis  of  flowers,  fruits,  and  bright-hued 
mates.  But  in  man  the  aesthetic  pleasure  in  colour  be- 
comes strongly  marked,  being  found  amongst  the  very 
lowest  savages,  and  entering  into  every  department  of 
industry  amongst  the  civilised  races.  From  the  red  ochre 
and  brilliant  feathers  of  the  naked  Andamanese,  up  to  the 
paintings  and  decorations  of  European  palaces,  we  can 
trace  its  gradual  development  from  stage  to  stage,  becom- 
ing more  and  more  divorced  from  life-serving  function 
with  every  onward  step,  until  at  last  the  a3sthetic  senti- 

1  See  chap,  viii.,  ante. 
2  See  my  "Physiological  -iEsthetics,"  chap.  iii.  and  passim. 


THE  ESTHETIC  VA  ^^JE  OF  COLOUR.  223 

menfc  claims  to  rank  with  th*      .oral  feelings  among  the 
most  disinterested  elements  of  our  nature. 

The  simplest  aesthetic  feelings  precede  the  more  com- 
plex, and  the  vivider  precede  the  fainter.  Hence  progress 
in  aesthetics  consists  largely  in  the  constantly  increasing 
appreciation  of  more  and  more  delicate  forms  of  pleasure, 
coupled  M'ith  the  constantly  increasing  sensitiveness  to 
more  and  more  delicate  shades  of  discord  or  unpleasantness. 
The  earliest  aesthetic  objects  to  obtain  notice  will  be  those 
which  most  strongly  excite  the  whole  nervous  organisation; 
the  more  delicate  and  special  stimulants  will  not  be  prized 
until  a  later  stage  of  evolution.  Thus  children  and  savages 
are  pleased  with  the  mere  coarse  excitement  of  a  drum  or 
a  tom-tom :  only  after  careful  training  can  they  rise  to 
comprehend  the  more  dainty  distinctions  of  melody  and 
harmony..  The  overpowering  perfumes  of  musk  and 
ambergris  are  appreciated  long  before  the  delicate  sweet- 
ness of  the  violet  and  the  primrose.  And  in  like  manner, 
the  powerful  stimulation  of  brilliancy  is  sooner  understood 
than  the  milder  stimulation  of  the  analytic  colours. 

Bright  light  affects  all  the  nervous  elements  of  the  eye 
at  once ;  the  various  colours  only  affect  one  set  of  elements 
at  a  time.  Whatever  view  we  may  adopt  with  regard  to 
the  mechanism  of  colour-perception,  whether  that  of  Young 
and  Helmholtz,  or  those  of  their  late  critics,  it  is  at  least 
certain  that  the  direct  total  beam  rouses  a  greater  sum  of 
sensation  in  the  optic  nerve  and  its  connected  centres  than 
is  aroused  by  any  one  of  the  separate  components,  say  for 
example  the  green  or  the  blue  rays.  Hence  we  find  that 
brilliancy  seems  to  be  more  prized  by  savages,  and  perhaps 
by  the  lower  animals,  than  pure  colour.  A  few  examples 
will  serve  to  show  the  truth  of  this  generalisation. 

Amongst  animals,  passing  over  the  doubtful  cases  of  the 
glow-worm,  the  fire-flies,  and  the  phosphorescent  species 
generally,  we  have  in  the  attraction  of  most  flying  insects 
towards  the  flame  a  distinct  proof  of  the  effects  produced 
by  brilliancy.     So,  too,  we  know  that  many  of  the  higher 


224  THE  r     LOUR-SENSE. 

animals  seem  instinctivi  drawn  by  tlie  glow  of  fire ;  and 
though  they  will  not  approach  it  too  closely,  tliey  show 
decided  signs  of  interest  in  its  bright  glare.  This  same 
feeling  reappears  in  the  savage  love  for  torchlight  dances, 
for  bonfires,  and  for  like  rude  pyrotechnic  displays  ;  while 
it  reaches  its  culminating  point  in  fire- works,  in  illumina- 
tions, in  Guy  Fawkes  celebrations,  and  in  similar  civilised 
exhibitions  of  coarse  visual  stimulation.  In  every  case  we 
feel  at  once  that  the  aesthetic  pleasure  involved  belongs  to 
the  very  lowest  stratum  of  its  class,  the  stratum  which  we 
Europeans  share  in  the  greatest  degree  with  the  savage 
members  of  our  race.  Children  and  uncultured  adults_ 
delight  in  the  rude  shocks  of  a  fire-work  exhibition,  but_ 
sensitive  eyes  and  minds  shrink  from  the  excessive  demand, 
upon  optic  nerve  and  brain. 

Keflected  glitter  or  lustre  ranks  next  in  aesthetic  order 
among  the  visual  stimulants.  It  still  exercises  the  whole 
sentient  organ,  but  not  with  such  violence  as  the  pre- 
ceding class.i  Amongst  animals,  the  taste  for  glitter 
is  shown  by  the  attraction  of  fish  towards  a  spoon  or 
other  bright  substance,  by  the  magpie  love  for  secreting 
diamonds  and  jewellery  generally,  and  by  the  common 
practice  of  drawing  down  larks  to  the  reflected  light  of 
a  mirror.  The  objects  collected  by  the  bower-birds  are 
often  lustrous,  such  as  shells  and  smooth  pebbles.  The 
more  beautiful  animals  also  show  a  great  tendency  towards 
iridescence  or  metallic  tints,  which,  though  they  contain 
a  large  element  of  pure  colours,  include  likewise  a  great 
deal  of  mere  direct  reflexion.  Cases  in  point  are  found 
among  beetles,  butterflies,  humming-birds,  sun-birds,  and 
lizards.  Glossiness  frequently  occurs,  apparently  as  a 
sexual  device,  in  the  fur  of  mammals.     Amongst  mankind, 

1  It  may  be  noticed  in  passing  that  our  admiration   of  the  milder  brilli- 

our  enjoyment  of  fire-works,  bonfires,  ancy  of  gems  and  crystals  belongs  to 

glow-worms,   and  fire-flies,  is  mainly  the   day-time,   and  th'5  recuperative 

confined  to  the  night,  when  we  can  interval  is  gained  by  gjanciug  rapidly 

recuperate  our  powers  of  vision  dur-  at  other  objects, 
ing  the  intervals  of  darkness  ;  while 


THE  ESTHETIC  V^^iVff.  OF  COLOUR.  225 

the  love  for  glittering  ornamtg  .-.  certainly  appears  to  be 
very  deep-seated,  and  perhaps  preceded  that  for  colour  as 
an  sesthetic  adjunct.  At  any  rate,  teeth,  shells  (especially 
cowries,  which  are  naturalhj  polished  by  the  overlapping 
of  the  animals'  bodies),  bones,  flints,  metals,  and  like 
lustrous  materials,  form  very  common  adornments  of 
savage  or  prehistoric  races.  And  with  ourselves,  the  love 
for  gilding,  for  excessive  polish,  for  shiny  and  glaring 
materials,  is  a  well-known  symptom  of  had  taste — that 
is  to  say,  it  is  recognised  as  belonging  to  the  common  and 
universal  coarse  class  of  pleasures,  not  to  the  more  delicate 
kind  which  offers  greater  attractions  to  the  sesthetically 
refined. 

A  few  more  examples  of  the  taste  for  lustre  may  here 
be  fittingly  introduced,  as  leading  up  to  the  more  restricted 
esthetic  pleasure  of  colour.  Shells  and  bones  form  the 
chief  natural  decorations  of  savages,  especially  when 
polished  by  use.  Fossils  of  shiny  texture,  drilled  to  serve 
as  beads,  occur  in  palaeolithic  deposits.  Mother-of-pearl 
and  real  pearls  are  always  prized  for  personal  adornment. 
Among  stones,  carnelian,  jade,  jet,  and  crystals  are  in  high 
request.  Long  before  the  historic  period,  a  regular  trade 
brought  amber  from  the  Baltic,  or  lapis  lazuli  from  Persia, 
to  Mycense  and  Troy.  Professor  Eollestone  informs  me 
that  stone  implements  are  found  in  Western  Europe  of  a 
material  which  could  not  be  obtained  nearer  than  the 
mountains  of  Central  Asia.  Similarly,  the  common 
hatchets  of  the  West  Indies  were  imported  from  the 
mainland,  the  bright  green  stone  of  which  they  are  made 
not  being  found  anywhere  in  the  Archipelago.  Our  own 
modern  taste  for  rubies,  diamonds,  sapphires,  and  topazes 
is  directly  derived  from  the  usage  of  savages.  Ivory, 
tortoise-shell,  Job's-tears,  gru-gru  nuts,  and  other  organic 
products  capable  of  receiving  a  high  polish,  have  always 
been  greatly  prized  by  unsophisticated  aborigines.  Marble, 
alabaster,  satinstone,  and  granite  .deserve  mention  in  the 
same    connection.     Cocoa-nut   cups,    clubs,  war-canoes, 


226  THE  Cny.OUR-SENSE. 

skulls  for  drinking  gobi  -  'and  like  artistic  utensils,  in- 
variably receive  a  glossy  surface.  Glass  and  the  art  of 
glazing  pottery  yield  proofs  of  the  same  universal  taste. 
Lastly,  the  inventions  of  lacquer,  varnish,  boot-blacking, 
and  other  artificial  means  for  imparting  lustre  to  naturally 
dull  surfj^ces,  derive  their  origin  from  a  similar  source. 

But  among  all  the  lustrous  objects  which  attract  the 
nascent  aesthetic  faculty  of  primitive  man,  none  are  more 
important  in  their  final  effects  than  metals.  Leaving  out 
of  consideration  as  too  remote  from  our  present  subject 
the  numberless  uses  of  copper,  bronze,  tin,  iron,  and  steel, 
it  will  be  enough  if  we  glance  briefly  at  the  employment 
of  silver  and  gold.  These  had  at  lirst  no  other  recom- 
meudation  than  their  immediate  beauty,  and  they  were 
collected  for  the  manufacture  of  goblets,  masks,  torques, 
beads,  earrings,  and  articles  of  personal  adornment.  But 
in  the  course  of  time  they  became  utilised  as  a  medium 
of  exchange,  owing  both  to  the  general  request  in  which 
they  were  held,  and  to  the  ease  with  which  they  could  be 
divided  and  reunited.  Hence  at  the  present  day  mankind 
still  carries  on  its  commerce  by  bartering  goods  against 
the  very  self-same  bits  of  shiny  white  or  yellow  metal 
which  once  hung  round  the  naked  necks  of  African, 
American,  and  prehistoric  chieftains. 

Passing  on  from  the  general  stimulation  of  the  total 
light-beam,  direct  or  reflected,  to  the  partial  stimulation 
of  its  various  components — the  analytic  colours — we  have 
V  next  to  inquire,  Has  any  one  colour  a  decided  aesthetic 
superiority  over  any  other  ?  The  answer  must  distinctly^ 
be.  Yes.  The  red  and  orange  end  of  the  spectrum  js 
decidedly  the  most  pleasurable :  while  the  central  colours, 
green  and  blue,  are  decidedly  the  least  so.i 

Many  separate  reasons  conduce  to  this  effect.  In  the 
first  place,  we  have  already  seen  that  greens  and  blues  are_ 

1  I  have  discovered  experimentally  that  of  colour  ;  and  that  amongst 
that  infants  respond  to  the  stimula-  colours,  red  is  the  first  to  attract 
tion  of  light  before  they  respond  to    their  attention. 


THE  ESTHETIC  VALUE  OF  COLOUR.  227 

by  far  the  commonest  colours  in  nature,  being  those  of 
the  whole  grass-clad  fields,  forest  stretches,  and  wide 
ocean  below,  and  also  of  the  great  open  sky  overhead. 
On  the  other  hand,  red  and  orange  are  by  far  the  most 
unusual  hues,  being,  practically  speaking,  unknown  in  the 
ordinary  inorganic  environment,  and  only  found  in  a  few 
minor  parts  of  animal  or  vegetal  organisms.  Hence  the 
structures  in  our  eyes  which  are  percipient  of  red,  are  far 
less  frequently  exercised  than  those  which  are  percipient 
of  green  and  bhie.i  So  it  will  follow  that  they  are  gene- 
rally in  that  highly  unstable  and  fully-nurtured  state  in 
which  they  are  capable  of  pleasurable  stimulation.  The 
structures  for  the  perception  of  green  and  blue,  on  the 
contrary,  being  habitually  stimulated  to  the  proper  extent, 
do  not  yield  any  specially  agreeable  feelings  under  ordi- 
nary circumstances. 

Again,  the  luminous  intensity  of  red,  orange,  and 
yellow  is  considerably  greater  than  that  of  green,  blue, 
and  violet.  Hence  their  stimulating  powers  may  be 
plausibly  considered  as  greater  than  those  of  the  less 
luminous  colours.  I  am  glad  to  be  able  to  state  that  I 
owe  this  suCTo-estion  to  Dr.  Mamus  and  Mr.  Gladstone. 
It  is,  doubtless,  to  their  higher  luminous  qualities  that 
the  red  and  orange  rays  owe  that  pungency  and  strength 
which  is  one  of  their  distinguishing  characteristics.  They 
may  be  considered  to  approach  nearest  in  this  respect  to 
the  brilliancy  of  direct  total  light. 

1  Some  of  the  critics  wlio  kindly  Sciences,"  vol.  xiii.  p.  402,  of  wliich 

noticed  my  work  on   "Physiological  I  have  given  an  abstract  in  "Mind," 

Esthetics,"  seem  to  have  supposed  for  January  1879),  it  must  at  least  be 

that  the  truth  of  this  result  would  allowed  that  the  centres  percipient 

depend     upon     our     acceptance     of  of  red   cannot   be   the   same   as  the 

Young's  theory  of  colour-perception,  centres  percipient  of  green  and  blue, 

with  which   it   was  there  affiliated.  Accordingly,  they  must  be  usually  in 

Such,  however,  is  not  necessarily  the  a  comparatively  high  state  of  nutri- 

case.    Whatever  may  be  the  ultimate  tion,    fitted    for    the    production   of 

mechanism  of   the    nerve  terminals  pleasurable  sensations.     In  fact,  the 

for  the  receijtion  of  colour-stimula-  conclusion  rests    upon    the    general 

tion   (see  an  able  paper  by  Mr.  G.  conditions  of  sensibility,  and  is  quite 

Stanley  Hall,  in  the  "  Proceedings  of  independent  of  any  particular  theory 

the  American  Academy  of  Arts  and  of  vision. 


N^ 


228  THE  COLOUR-SENSE. 

But  above  either  of  these  causes  we  may  place,  I  think, 
the  hereditary  tendency  of  the  human  eye,  derived  from 
our  early  frugivorous  ancestors.  Eed,  orange,  and  yellow 
arc  the  common  hues  by  which  fruits  may  be  distin- 
guished from  the  surrounding  masses  of  green  foliage. 
Accordingly,  the  eyes  of  frugivorous  animals  must  be  con- 
tinually on  the  alert  for  such  colours ;  and  the  organs  for 
their  perception,  besides  being  immediately  strengthened, 
must  also  gain  numerous  connections  with  other  nervous 
centres,  which  will  permit  the  escape  of  comparatively 
voluminous  emotional  waves.  I  do  not  mean  that  these 
colours  will  come  to  be  intellectually  associated  with  the 
pursuit  of  food,  for  although  such  is  doubtless  the  case, 
that  fact  would  not  in  itself  suffice  to  account  for  the 
pleasure  aroused ;  but  I  mean  that  the  increased  calibre 
of  the  nervous  organs  thus  exercised,  and  the  number  of 
additional  channels  thus  provided  for  the  overflowing 
nervous  energy,  would  conspire  to  produce  a  direct  and 
immediate  sensuous  pleasure.  This  pleasure  would  result 
from  the  mere  act  of  perceiving  red,  not  from  the  mediate 
recognition  of  red  as  a  symbol  of  food. 

From  the  combination  of  these  three  causes,  it  happens 
that  the  sensation  of  red  or  orange  is  the  most  agreeable 
of  all  the  pure  colour-perceptions.  And  as  the  earliest 
and  least  cesthetically  developed  races  pay  attention  only 
to  the  strongest  stimulants,  leaving  out  of  consideration 
the  more  delicate,  we  may  say  roughly  that  amongst  all 
savage  tribes  red  is  'par  excellence,  and  above  all  others  the 
decorative  colour.  Dr.  Magnus  has  noted  this  fact,  and 
uses  it  as  an  argument  in  favour  of  his  theory  that  rec 
formed  the  first  part  of  the  visible  spectrum  to  be  sepa- 
rately cognised  by  the  human  eye.  Mr.  Gladstone  speaks 
of  "  the  prominence  which  that  colour  acquired  both  in 
the  initial  stages  of  the  painter's  art,  and  in  the  costumes 
of  high  personages.  It  had,  as  it  were,  got  a  start,  and  ha 
the  first  possession  of  the  ground,  which,  in  costume  pai 
ticularly,  it  has  retained.     But,"  continues  the  author,  an 


THE  ^ESTHETIC  VALUE  OF  COLOUR.  229 

h  ere  I  am  pleased  that  I  can  thoroughly  agree  with  him, 
"  vwe  must  remember  that,  in  public  exhibition  and  cere- 
rcConial,  it  is,  from  its  luminous  character,  highly  satisfac- 
topry  to  the  eye."  Of  course,  we  must  further  remember 
tl>iat  red  forms  the  favourite  colour,  not  only  of  primitive 
n^.ian  and  of  modern  savages,  but  also  of  the  young  and 
tile  coarse-natured  among  our  European  nations.  The 
Oentral  African  is  bribed  with  yards  of  red  calico ;  the 
West  Indian  negress  adorns  herself  in  a  red  turban ;  the 
bfJiby  in  its  cradle  jumps  at  a  bunch  of  red  rags ;  the 
LMdon  servant-maid  trims  her  cap  with  scarlet  ribbons, 
ai^d  admires  the  soldier's  coat  as  the  most  beautiful  of 
hiaman  costumes. 

:  But  there  exists  yet  another  and  more  mechanical  reason 
w  hy  red  came  early  into  favour  for  decorative  purposes. 
Olf  all  primitive  pigments,  by  far  the  commonest  and  easiest 
t(<^  obtain  are  ochreous  earths.  Blue  dye  can  only  be  ex- 
triacted  in  an  early  culture  from  certain  vegetal  substances, 
wihich  require  comparatively  advanced  skill  for  their  pro- 
di^ction ;  w^hile  greens  are  chiefly  obtained  from  minerals 
of  rare  occurrence.  But  red  earths  may  be  found  almost 
everywhere,  and  the  method  of  their  application  is  as 
si:iiple  as  the  ruddling  of  sheep.  Hence  we  find  traces  of 
thje  use  of  ochre  where  scarcely  any  other  pigments  are 
kitiown.  Lumps  of  red  clay  lie  beside  the  prehistoric 
dead  in  their  rude  barrows  ;  and  red  stains  for  the  body 
compose  the  chief  decoration  of  modern  savages.  Almost 
everywhere  that  we  find  mention  of  red  pigment  amongst 
uncivilised  races,  inquiry  shows  that  ochre  is  the  material 
from  which  it  is  obtained.  Thus  the  New  Zealanders 
paint  their  skins  red — with  ochre ;  the  Bushmen  in  like 
manner  redden  their  bodies — with  ochre;  the  people  of 
the  Congo  do  the  same — with  ochre.  Of  the  Australians, 
the  Tasmanians,  the  Fuegians,  the  Tannese,  the  Andaman 
Islanders,  I  see  it  similarly  mentioned  that  they  employ 
ochre  for  their  personal  decoration.  So,  too,  in  higher  arts, 
the  red  and  yellow  of  the  Trojan  and  Mycenean  pottery 


230  THE  COLOUR-SENSE. 

are  clay  colours.  The  Egyptian  red,  as  we  have  already 
seen,  was  "  an  earthy  bole,"  and  the  yellow  "  an  iron  ochre-" 
Even  among  ourselves  ruddle  still  performs  many  usefi^l 
functions,  and  ranks  as  the  simplest  and  easiest  means  of 
making  distinguishing  marks  on  animals,  sacks,  and  other 
rural  objects. 

Occasionally  the  origin  of  the  red  pigment  is  slightly 
different.  The  Samoans,  I  learn  from  Mr.  Whitmee,  u^e 
a  volcanic  earth  for  this  purpose;  the  Assyrian  reiji, 
according  to  Sir  A.  Layard,  w^as  a  sub-oxide  of  coppe\'; 
and  Mr.  E.  S.  Morse  records  the  discovery,  in  prehistoric 
shell-heaps  at  Omori  in  Japan,  of  pottery  coloured  crimsan 
with  cinnabar.^  But  whatever  the  material  employed,  W'e 
always  see  that  the  red  end  of  the  spectrum  possessed  and 
still  possesses  peculiar  attractions  for  undeveloped  eesthetic 
tastes.  I 

Besides  the  employment  of  red  for  sesthetic  purposes  in 
the  shape  of  pigment,  we  may  also  note  its  use  in  other 
shapes.  For  example,  there  is  the  case  of  the  red  pebblfes 
and  the  pretty  polished  lola  mentioned  above.^  The  Mexi- 
cans used  orange  feathers  for  many  decorative  appliances ; 
and  the  well-known  cloaks  of  the  Hawaiian  kings  were 
composed  of  the  beautiful  plumage  of  Mdithreptes  pacifica 
(note  the  name — as  might  be  expected,  a  honey-feeder). 
The  crimson  hibiscus  is  a  favourite  flower  amongst  the 
West  Indian  negroes,  whose  huts  may  generally  be  descried 
at  some  distance  by  means  of  its  massive  blossoms.  And 
I  find  the  same  brilliant  flower  twice  mentioned  by  Lord 
George  Campbell  as  a  decoration  of  the  person,  once  in  the 
case  of  a  girl  at  Kandavu,  Fiji,  and  again  in  the  wigs  of 
the  savage  Papuans  at  Humboldt  Bay.^ 


1  Nature,  Nov,  29,  1877.  will  forgive  me.    But  whenever  a  tp- 

-  In  this  chapter,  where  I  am  pre-  ference  has  already  been  appendec;    1 

senting  the  facts  in  a  slightly  different  do  not  think  it  necessary  to  repeat  i : 

point  of  view,  I  am  compelled  un-  here. 

avoidably  to  repeat  some  of  the  in-  ^  Log-Letters  from  the  Challenr,r, 

stances   given  in   the   preceding  one,  pp.  150-249. 

for  which  repetition  I  trust  the  reader 


THE  /ESTHETIC  VALUE  OF  COLOUR.         231 

Next  to  red  (with  which  must  be  included  orange  and 
yellow)  in  the  order  of  aesthetic  appreciation  comes  blue. 
This  colour  is  comparatively  common  in  nature,  being  the 
hue  of  the  clear  sky  (in  a  few  rare  conditions  only,  for  the 
sky  of  cloudy  countries  is  whity-grey,  and  that  of  the 
tropics  an  indefinite  haze),  as  well  as  of  the  enclosed  sea 
in  bays.^  Moreover,  it  is  wanting  in  luminous  intensity, 
and  is  therefore  very  far  from  being  a  pungent  colour. 
However,  in  the  third  factor  of  asthetic  effectiveness,  the 
hereditary  tendency  of  humanity,  blue  is  doubtless  com- 
paratively strong;  for  a  large  number  of  fruits  have  a 
more  or  less  bluish  or  purplish  tinge.  Accordingly,  it 
ranks  second  in  development  amongst  the  favourite  colours 
of  mankind.  Wherever  only  two  hues  are  employed  in 
decoration,  those  hues  are  generally  red  and  blue.  Indeed,  "^ 
if  we  use  at  random  two  words  as  summing  up  the  totality 
oj  our  colour-tastes,  those  two  words  wdll  be  red  and  blue. 
^'"  ellow  is  aBsthetically  a  mere  species  of  red,  while  green 
Idas  very  little  pleasurable  effect,  except  to  highly- cultivated 
eyes. 

^  Accordingly,  wherever  a  blue  pigment  exists  in  an  ac- 
cessible form,  the  use  of  blue  is  common.  We  have  seen 
already  that  blue  enamel,  blue  glass  beads,  and  blue  lapis 
lazuli  occur  in  prehistoric  remains ;  but  the  want  of  a 
proper  dye  seems  generally  to  have  prevented  its  popular 
use."  Thus,  while  the  Egyptians  and  Assyrians  employed 
it  abundantly,  no  trace  of  it  occurs  upon  the  Trojan  or 
Mycenean  pottery.  But  the  ancient  Welsh  stained  their 
bodies  with  woad,  and  all  the  Polynesian  races'  tattoo 
themselves  in  blue  lines.  Many  of  the  lowest  Indian  hill 
tribes — Kukis,  Nagas,  Todas,  and  Santals — use  indigo  for 
dyeing  cloth.  The  same  dye  is  also  widely  employed 
throughout  Central  Africa.     The  bluish  purple  Bougain- 

1  I  know  no  commoner  instance  of  sea  are  blue.     It  is  only  true,  when 

the  inaccuracy  of  ordinary  language  carefully  tested,  in  about  one  experi- 

with  regard  to  colour  than  the  fumi-  ence  out  of  fourteen, 
liar  statement  that  the  sky  and  the 


232  THE  COLOUR-SENSE. 

villea  almost  vies  with  the  crimson  hibiscus  in  the  favour 
of  savages ;  and  Bonwick  mentions  by  name  white,  red, 
and  blue  species  of  flowers  used  by  the  Tasmanians  in 
personal  decoration.^ 

_Green  appears  -to-jaia-the  least  effective  resthetically  of 
all  colours  :|J  mean,  of  course,  to  the  ordinary  mass  of 
mankind,  for  it  must  be  remembered  that  the  cultivated 
taste  generally  gives  a  verdict  exactly  opposed  to  that  of 
the  multitude.  It  is  the  commonest  of  all  colours  in  the 
natural  environment  of  man ;  it  has  but  little  luminous 
intensity;  audit  is  not  connected  hereditarily  with  any 
special  function.  Accordingly,  I  find  it  seldom  mentioned 
among  the  decorative  colours  employed  by  savage  tribes, 
and  even  then  it  is  usually  introduced  as  a  contrast  to 
red.  While  the  Santals  wear  strips  of  red,  blue,  and 
yellow  cloth ;  while  the  Nagas  dress  in  white  cotton  with 
red  and  blue  fringes ;  I  do  not  meet  with  any  mention  fli' 
green  dyes  among  the  Indian  hill  tribes.  And  this  is  vet^e 
natural  if  we  recollect  that,  amid  their  green  leafy  sur-| 
roundings,  it  would  yield  A^ery  little  contrast  and  posses^ 
very  little  decorative  value.  However,  as  we  mount  in  thi3 
scale,  we  find  that  the  women  of  New  Guinea  dye  their 
petticoats  red  and  green,  with  intermediate  strips  of 
yellow;  while  the  Ashantis  employ  all  four  decorative 
colours,  red,  blue,  yellow,  and  green.  Of  course,  with  the 
Mexicans,  Peruvians,  Egyptians,  and  Assyrians,  all  these 
colours  were  in  common  use,  and  green  was  raised  to  a 
place  of  equal  importance  with  red  and  blue. 

Yet,  as  a  rule,  where  green  rises  to  the  position  of  a 
decorative  colour,  I  am  inclined  to  think  that  we  can 
usually  trace  a  special  reason  in  the  circumstances  of  the 
particular  race.  Green  forms  the  opposite  pole  from  red, 
in  that  red  is  the  pungent  and  stimulative  colour,  while 
green  is  the  restful  and  reparative  colour.  Owing  to  the 
larcre  amount  of  green  in  the  natural  environment,  our 

1  Daily  Life  of  the  Tasmanians,  p.  27. 


THE  ESTHETIC  VALUE  OF  COLOUR.  233 

eyes  appear  to  be  adapted  for  continuous  languid  stimula- 
tion by  that  gentle  excitant,  which  forms  the  mean  of  the 

I     total  spectrum.    On  the  other  hand,  owing  to  the  ancestral 

[  habits  of  our  race,  our  eyes  appear  to  be  adapted  for  sudden 
and  pleasurable  excitation  by  red,  which  rapidly  glides  into 

I     fatigue.     Accordingly,  we  desiderate  green  as  a  relief.    In 

I  tHe  normal  circumstances  of  humanity,  surrounded  by 
trees  and  fields,  this  relief  is  abundantly  present.  But 
in  the  civilised  cities,  with  their  greys  and  stone-blues, 
green  does  not  occur  with  sufficient  frequency,  and  hence 
it  is  hailed  as  a  fresh  and  pleasant  change.     Added  to 

^"^Vhich,  it  is  joined  in  the  civilised  mind  with  various 
associated  emotions,  either  actually  felt  or  dimly  sug- 
gested. And  as  its  pleasure  is  the  least  directly  stimulat- 
ing, the  most  gentle  and  modest  of  all,  it  naturally  ranks 
highest  of  any  colour  in  the  hierarchy  of  the  sesthetically 
cultivated. 

^        ISTow,  it  would  seem  as  though  the  use  of  green  in 

flecoration   were   almost    exclusively   confined   to   those 

Jpeople  who  live  an  indoor  life.     It  is  among  the  civilised 

'"''^or  semi- civilised  nations  that  we  see  it  most  employed; 
and  where  it  is  found  in  the  case  of  savages  (as  the 
Samoans  and  Hawaiians)  it  has  generally  been  introduced 
from  Europe  or  America.  Moreover,  it  seems  to  be  in 
special  favour  among  the  Persians ;  ^  and  it  may  perhaps 
be  suggested  that  Persia  is  a  peculiarly  arid  country,  where 
green  is  decidedly  wanting  in  the  landscape.  It  also  ranks 
high  among  the  Arabs,  and  among  many  inhabitants  of 
cold  climates.  Those  who  have  seen  a  Canadian  Christmas, 
w^ith  its  monotonous  field  of  snow  outside,  and  its  gay 
decorations  of  evergreens  and  red  berries  indoors,  will 
thoroughly  understand  the  rationale  of  this  preference. 

To  the  last,  the  use  of  green  remains  chiefly  supple- 
mentary. It  is  employed  in  bouquets  as  a  relief,  and 
in   decorations   as   an  element  with  red  and  blue;    but 

1  Von  Bezold,  Theory  of  Colour,  American  translation,  pp.  212,  215. 


234  THE  COLOUR-SENSE. 

Ly  itself  it  must  be  regarded  as  the  least  efficient  of  all 
colours. 

It  shou^a  be  added,  however,  that  from  the  beginning 
green  seems  to  have  been  prized  in  such  permanent  forms 

as  jewels  or  stones.      Sea-green  pebbles  are  mentioned  | 

among  those  buried  in  the  barrows  :  and  jade  ranks  as  one  '\ 

of  the  commonest  materials  for  polished  hatchets.    Green-  ■ 

stone,  green  jasper,  and  light  green  slate  are  also  frequently  I 

employed  for  like  purposes ;  and  emeralds,  malachite,  or  ! 

other  similar  minerals,  have  been  universally  prized  for  ■ 

their  beauty.     The  Central  American  and  South  American  j 

Indians  seem  to  have  had  an  extraordinary  taste  for  green  | 

jewels,  for  which  I  confess  I  can  see  no  sufficient  reason.  ,     ! 

Perhaps  it  may  have  depended  simply  upon  an  accidental^  ^ 

frequency  of  such  stones  in  that  tract  of  country.     How4  L  \ 

ever,  an  explanation  is  here  certainly  desirable.  U 

On  the  other  hand,  children  and  savages  take  little 

notice  of  vegetal  greens,  and  usually  arrange  red  and  blue  ,  ^ 

flowers  entirely  by  themselves,  without  that  admixture  ofi  i ' 

relieving  foliage  which  a  more  refined  taste  imperatively!  I 

demands.  ^^ 

As  regards  the  various  mixed  or  intermediate  colours —  j 

purple,  orange,  lilac,  mauve,  and  so  forth — their  effective-  j 

ness  depends  mainly  upon  their  similarity  to  red  on  the  i 

one  hand  or  blue  on  the  other.     In  proportion  as  they  , 

approach  green  they  are  less  and  less  pleasurable  :  while,  • 

of  course,  those  of  the  red  end  are,  on  the  whole,  greater  | 

favourites  than  those   of  the  violet.     Purple  forms  an  \ 

intermediate  term,  being  brilliant  in  the  exact  ratio  of  the  i 

red  rays  which  it  contains.     Of  course,  among  civilised  A 

people,   such   colours   possess   the   additional    charm   of  U 

novelty  and  variety.  I 

A  few  more  words  must  be  added  as  to  the  mode  in  [' 
which  the  various  colours  are  used.     In  the  earliest  stage 
they  are  merely  daubed  on  in  isolation,  as  by  the  Anda- 
manese  who  plasters  his  head  with  ochre,  or  the  ancient 
Welsh  who  stained  their  bodies   with  woad.     A  little 


THE  ESTHETIC  VALUE  OF  COLOUR.  235 

higher  up  in  the  scale,  the  colours  are  used  in  hars  or 
strips,  of  violent  contrast.  Black,  white,  and  red  are  the 
favourite  pigments,  each  being  well  pronounced  and 
standing  out  boldly  against  its  neighbour.  Then  conies 
the  addition  of  blue,  and  finally  that  of  green.  Above 
this  level  we  find  the  employment  of  intermediate  hues, 
such  as  yellow,  orange,  and  pink.  Last  of  all,  the  colours 
are  mixed  in  shades  of  varying  intensity,  and  we  get 
the  whole  wealth  of  the  entire  spectrum,  as  in  modern 
European  art. 

Again,  the  variety  of  form  gives  another  element  of 
evolution,  into  which,  however,  it  would  be  improper  to 
enter  in  the  present  volume,  restricted  as  it  is  to  the  exa- 
mination of  the  simple  colour-sense.  Here  it  must  suf- 
fice briefly  to  point  out  the  upward  movement  from  the 
simple  bars  or  strips  of  the  savage,  through  the  graceful 
curve  lines  of  the  Polynesians,  to  the  arabesques  and 
decorative  harmonies  of  the  Moors ;  or  from  the  red  and 
yellow  imitative  figures  of  the  Hawaiians,  through  the 
bright  primary  wall-paintings  of  the  Egyptians,  to  the 
landscapes  and  the  figure-pieces  which  adorn  the  walls  of 
Our  Salons  and  our  Academies. 

Both  these  lines  of  evolution,  however,  suggest  a  further 
consideration  of  great  importance.  While  primitive  man 
cares  only  for  the  pungent  and  brilliant  stimulation  of  the 
primary  colours,  in  all  their  fullest  intensity  of  light,  and 
pays  little  attention  to  their  darker  shades  or  duller  mix- 
tures, the  aesthetically  cultivated  have  learnt  to  notice  and 
iippreciate  the  fainter  pleasures  which  arise  from  these 
.t,lif]jhter  and  more  delicate  stimulations.  They  are  thus 
enabled  to  vary  and  enlarge  their  means  of  visual  grati- 
fication, and  to  dispose  their  various-coloured  objects  in 
Jar  more  numerous  and  more  subtle  combinations.  "While 
tlie  Australian  knows  only  two  or  three  invariable 
.Arrangements  of  red,  black,  and  white,  the  civilised 
decorator  is  able  to  ring  the  changes  perpetually 
tipon    ever- varying    harmonies    and    contrasts   of   faint 


236  THE  COLOUR-SENSE. 

yellows,  pale  Hues,  rich  purple-greys,  and  dark  olive- 
greens.  By  artfully  devising  here  a  stimulation,  there  a 
relief,  here  a  mass  of  comparatively  brilliant  pungency, 
there  a  field  of  mild  retiring  neutral  tints,  he  succeeds  in 
sustaining  and  recruiting  the  sensuous  pleasure  of  colour 
from  moment  to  moment,  without  ever  causing:  us  fatigue 
or  overtaxing  a  single  sentient  structure. 

And  now  we  must  pass  on  to  a  second  point  of  view, 
that  of  the  objects  which  are  employed  for  the  aesthetic 
gratification  of  the  colour-sense.  These,  on  the  whole, 
afford  a  strong  confirmation  of  the  theory  with  regard  to 
the  orig^in  of  our  aesthetic  feeling^  which  is  here  advocated, 
as  the  greater  part  of  them  consist  of  the  very  objects 
which  owe  their  development  to  the  colour-sense  of 
animals. 

Fruits  themselves,  though  their  utilitarian  associations 
prevent  them  from  standing  in  the  front  rank  of  aesthetic 
objects,  are  yet  undoubtedly  beautiful  in  colour  and 
shape.  And  when  we  survey  them  amid  their  native 
boughs,  few  lovelier  sights  can  be  found  than  the  brighter 
and  prettier  among  them.  An  orange  tree  laden  with  its 
golden  spheres,  an  apple  orchard  weighed  down  with  its 
ruddy  pippins,  a  holly-bush  covered  with  its  crimson  berries, 
are  some  of  the  most  exquisite  pictorial  sights  which  can 
be  seen  on  earth.  Especially  aesthetic  do  fruits  become, 
when,  as  in  the  case  of  the  rowan,  the  spindle-tree,  and 
the  solanum,  they  are  incapable  of  being  used  as  food,  and 
so  can  only  minister  to  the  pure  pleasure  of  sight.  In 
most  instances,  however,  the  beauty  of  fruits  falls  a  little 
short  of  the  aesthetic  limit  in  the  actuality,  at  least  when 
they  have  been  picked  and  are  ready  for  table.  Yet  even 
so,  when  decorated  with  green  leaves,  and  interspersed 
with  flowers,  their  falling  short  is  very  slight  indeed,  \i 
not  purely  hypercritical.  But  as  objects  of  pictorial 
imitation  they  have  always  been  in  high  favour ;  while 
they  enter  largely  into  the  composition  of  poetry,  as  ideal 
stimulants  of  aesthetic  feeling. 


THE  ESTHETIC  VALUE  OF  COLOUR.  lyj 

Nevertheless,  it  should  be  noted  that  fruits  in  the 
actuality  are  closely  allied  with  the  frugivorous  instincts 
of  our  race,  and  that  the  origin  of  our  whole  taste  for 
colour  may  still  be  clearly  descried  in  the  imprint  which 
they  have  left  upon  our  minds.  Every  child  naturally 
puts  a  bright-coloured  berry  into  its  mouth;  and  it  is 
difficult  to  keep  the  hands  of  urchins  off  the  scarlet 
clusters  of  the  arum  or  the  brilliant  crimson  fruits  of 
the  yam.  Even  babies  automatically  strive  to  place 
every  bright  object  which  they  see  between  their  lips ; 
and  the  sweetmeats  which  are  manufactured  for  their 
pleasure  bear  attractive  strips  of  red,  blue,  and  yellow 
colouring.  These  and  fifty  other  minor  indications  show 
us  from  moment  to  moment  that  the  developed  love  for 
colour  is  a  transference  of  feeling  from  its  original  alliance 
with  the  common  food-stuffs  of  the  species. 

The  aesthetic  pre-eminence  of  flow^ers  has  never  been 
doubted.  In  the  actuality  they  form  the  commonest 
decoration  of  the  savage  home  and  the  civilised  garden,  of 
the  labourer's  cottage  and  the  royal  palace.  In  imitation, 
they  have  been  barbarously  travestied  with  paper,  wax,  or 
feathers,  and  parodied  in  cotton  upon  bonnets,  hats,  or 
dresses.  In  the  direct  pictorial  representation  they  have 
been  favourite  subjects  of  artistic  handling  from  the  days 
of  the  Egyptians  downward.  And  as  elements  of  poetry, 
they  have  been  celebrated  from  the  rose  of  Sharon  and 
the  hyacinth  of  Homer  to  Wordsworth's  daisy  and  Tenny- 
son's lily.  But  we  must  not  forget  that  herein  we  are 
practically  confessing  the  identity  of  our  own  colour- 
tastes  with  those  of  the  bees  and  butterflies,  for  whose 
attraction  these  floral  gems  were  first  developed. 

Fruits  being,  so  to  speak,  the  primitive  and  positive 
element  in  our  love  for  colour,  flowers  may  be  regarded 
as  one  among  the  earliest  classes  to  which  the  feeling  is 
transferred.  Even  monkeys  are  not  wholly  insensible  to 
their  charms,  though  they  display  their  affection,  like  our 
own  little  children,  chiefly  by  pulling  to  pieces  the  objects 


238  THE  COLOUR-SENSE. 

of  their  regard.  We  have  no  evidence,  of  course,  whether 
primitive  man  cared  for  flowers;  but  the  presumption 
from  the  case  of  existing  savages  would  certainly  lead  us 
to  suppose  that  he  did.  I  have  already  noted  that  the 
Tasmanians  and  Australians  employ  bright  blossoms  in 
their  personal  decorations ;  and  the  South  Sea  Islanders 
positively  revel  in  garlands  and  nosegays.  Even  the 
stern  American  Indians  show  considerable  love  for  these 
bright  natural  objects,  and  I  find  it  noted  of  the  Chibcha 
women  that  they  wore  flowers  in  their  hair.  A  little  plot 
of  half -uncultivated  garden  commonly  surrounds  the  very 
rudest  huts.  As  to  ourselves,  so  far  as  my  observation 
goes,  I  am  inclined  to  think  that  our  children  notice 
flowers  as  soon  as  they  take  note  of  anything  which  is 
not  good  to  eat,  while  I  had  hard  work  in  Jamaica  to 
keep  the  hands  of  little  negroes  off  the  purple  and  crimson 
plants  in  my  garden-plot.  Finally,  our  own  conserva- 
tories, flower-shows,  and  floral  decorations  show  us  the 
same  taste  pushed  to  its  furthest  extreme.^ 

It  is  worth  while  to  observe,  en  passant,  that  though 
our  children  pick  bunches  of  flowers  they  never  pick 
bunches  of  leaves,  a  fact  full  of  import  as  to  the  aesthetic 
value  of  green.  Similarly,  although  adults  intersperse 
their  bouquets  with  foliage  as  a  relief,  they  seldom 
arrange  leaves  by  themselves.  If  they  do,  the  leaves 
must  present  some  special  feature,  like  those  of  ferns, 
which  attract  us  sometimes  by  their  exquisite  gloss,  some- 
times by  their  varied  and  minutely-symmetrical  forms. 
So,  too,  when  we  place  a  flowerless  plant  in  our  gardens, 
it  must  either  be  recommended  by  such  beauty  of  shape 
or  s^loss,  as  in  the  case  of  ferns,  Palma  Christi,  and  india- 
rubber  trees,  or  by  coloured  foliage,  as  in  the  case  of 
drac^na,  coleus,  caladium,  sedum,  and  the  other  pretty 
plants  at  present  so  much  in  fashion.     It  is  true  a  culti- 

1  Since  this  chapter  was  written,  A.  Lambert,  has  appeared  in  the 
a  most  learned  paper  on  "The  Cere-  "Nineteenth  Century"  Eeview  for 
monial  Use    of    Flowers,"    by  Miss    Sej^tember  187S. 


THE  /ESTHETIC  VALUE  OF  COLOUR.  239 

vated  mind  may  derive  as  much  pleasure  from  a  green 
leaf  as  from  a  scarlet  geranium  or  a  purple  hyacinth ;  but 
then  the  pleasure  in  the  former  case  is  much  more  in- 
direct, complex,  and  emotional,  and  in  the  latter  cases 
much  more  immediate,  pungent,  and  sensuous.  More- 
over, the  first  pleasure  is  personal  and  restricted;  the 
second  is  generic  and  universal.^ 

This  is,  perhaps,  the  fittest  place  to  advert  to  another 
curious  fact,  the  fact  that  all  our  sesthetic  feelings  seem 
most  deeply  bound  up  with  the  relics  of  our  original  out- 
door, arboreal  existence.  Fruits  and  flowers,  birds  and 
butterflies,  sweet  perfumes  and  songs  of  nightingales,  the 
green  fields  and  the  luscious  forests,  these  are  deep  and  , 
resonant  elements  in  our  perennial  love  for  beauty.  Mr.  ^ 
Herbert  Spencer  has  pointed  out  that  the  pleasures  of  a 
day  in  the  country,  of  wild  scenery,  and  of  free  wandering 
over  heath  and  moor,  are  largely  due  to  unconscious  recol- 
lections of  the  ante-civilised  state.  He  even  suggests  that 
the  enjoyment  of  a  picnic,  with  all  its  unconventional 
delights,  is  mainly  explicable  as  a  sort  of  temporary 
reversion  to  a  primitive  state.  Still  more  obvious  does 
this  become  to  those  who  have  ever  tried  a  fortnight  of 
camping-out  among  the  Thousand  Islands  of  the  St. 
Lawrence  or  the  beautiful  lakes  of  western  New  York. 
But  it  seems  to  me  that  we  may  go  further,  and  ascribe 
our  whole  love  of  colour,  perfume,  and  the  more  delicate 

1 1  should  like  here  to  notice,  paren-  individualities  in  order  to   find   out 

thetically,  an  objection  which  has  been  what  was  primitive  and   original  in 

urged  by  favourable  critics   against  our  sesthetic  nature,  after  discovering 

parallel  passages  in  my  "Physiolo-  which  we  may  proceed    to  explain 

gical    Esthetics,"   and    which    will,  what    is    derivative    and    advanced, 

doubtless,  be  urged  in  like  manner  But  I  confess  that  the  feelings  which 

against  the  above  sentence.     I  have  a  painter  shares  with  a  child  and  a 

been  accused  of  appealing  from  the  barbarian  appear    to  me  more    im- 

cultivated  feeling  of  the  artist  to  the  portant    subjects     for    philosophical 

uncultivated  feeling  of  the  child  and  investigation  than  the  feelings  which 

the  savage,  as  though  the  latter  were  he  only  shares  with  a  knot  of  some 

in  some  way  truer  and  better.     Such  half-dozen    associates   belonging  to 

has  never  been  my  intention.     I  have  the  same  highly-specialised  artistic 

only  meant  to  appeal  to  the  simplest  school. 


240  THE  COLOUR-SENSE. 

taste  of  fruits,  to  half-remembered  habits  of  our  early 
ancestry.  The  acquired  carnivorous  mode  of  life  sits 
loosely  on  the  outer  layer  of  our  nature ;  but  the  hereditary 
frugivorous  instincts  seem  to  shape  all  our  inmost  feel- 
ings and  sentiments.  Bright  hues,  fragrant  scents,  sweet 
juices,  these  form  the  earliest  pleasures  of  childhood,  and 
remain  throughout  as  the  main  sensuous  factors  of  our 
aesthetic  nature.  The  very  fact  of  their  comparative 
remoteness  from  our  acquired  and  civilised  habits  seems 
to  make  them  all  the  more  distinctively  beautiful  and 
delicate.  Thus,  our  modern  dinner  a  la  Eusse,  by  re- 
moving from  the  table  the  coarse  elements  of  meat  and 
fish,  while  loading  the  white  damask  with  flowers,  with 
beautiful  fruits,  with  coloured  glass  and  porcelain  dessert 
service,  seems  to  recall  whatever  is  loveliest  and  most 
a^thereal  in  our  ancestral  traits.  On  a  humbler  scale,  the 
mere  decoration  of  dishes  with  parsley  or  watercress,  the 
bouquet  placed  in  the  centre  of  the  dinner  table,  and  the 
very  addition  of  cochineal  to  the  jellies,  or  of  Qgg  and 
beetroot  to  the  salad,  points  dimly  back  to  the  same 
half-obliterated  habits,  asserting  themselves  strongly 
throughout  our  whole  history. 

Both  fruits  and  flowers  are  comparatively  evanescent 
sesthetic  objects.  They  soon  fade  and  lose  their  beauty. 
But  feathers,  which  perhaps  rank  next  in  order  of  historical 
occurrence,  retain  their  brilliant  hues  for  a  considerable 
period.  And  just  as  our  sense  for  the  beauty  of  fruits 
and  flowers  is  a  proof  of  the  community  of  taste  which 
exists  between  frugivorous  man  and  the  fruit-eating  and 
flower-feeding  animals, — the  parrots,  toucans,  humming- 
birds, bees,  and  butterflies, — so  our  sense  for  the  beauty  of 
feathers  is  an  echo  of  the  taste  which  originally  produced 
them  by  sexual  selection  in  the  species  to  which  they 
belons.  Feathers  form  almost  universal  ornaments  of 
savage  or  civilised  humanity.  The  American  Indians 
thrust  them  into  their  head-dress  in  the  shape  of  a  crest 
or  crown.     The  Hawaiians  wove  from  them  their  famous 


THE  ESTHETIC  VALUE  OF  COLOUR.  241 

cloaks  and  idols.  The  Mexicans  employed  them  for  their 
beautiful  mosaics.  Eastern  nations  early  prized  the  pea- 
cock for  his  splendid  tail-plumes.  And  now,  in  our 
barbarous  civilisation,  millions  of  humming-birds  from 
Trinidad  and  South  America  come  yearly  to  Europe  for 
the  bonnets  of  our  English  ladies;  ostrich-farms  at  the 
Cape  supply  our  savage  court-dress  ;  and  marabou  plumes 
decorate  the  heads  of  our  Belgravian  beauties.  The  bird- 
of-paradise  forms  a  regular  article  of  commerce ;  grebe 
and  swans'  down  line  our  mantles  and  jackets ;  even  our 
very  funerals  are  surmounted  with  the  black-dyed  nodding 
plumage  of  tropical  birds.  Our  military  officials  wear 
feathers  as  the  mark  of  highest  distinction ;  and  the  heir- 
apparent  to  the  British  crown  uses  them  as  his  armorial 
cognisance.  Is  it  not  worth  noting,  too,  as  a  symptom 
of  the  permanent  character  which  marks  governmental 
ceremonial,  that  the  use  of  feathers  is  especially  bound 
up  with  our  military  system  and  court  etiquette  ?  Have 
w^e  not  here  a  direct  survival  from  the  simple  ornaments 
of  the  savage  chief  ? 

ISText,  perhaps,  in  our  conjectural  order  of  transference 
might  come  the  taste  for  shells,  pearls,  coral,  and  like 
organic  substances.  This  taste  we  find  almost  universal 
among  modern  savages,  and  it  extends  far  back  into  the 
prehistoric  age.  Mother-of-pearl  is  a  favourite  ornamental 
material,  which  has  retained  its  popularity  into  modern 
times.  ]N'ecklets  of  cowries  or  the  turbo  are  common 
savage  adornments,  which  have  not  yet  died  out  in  civi- 
lised lands.  Coral  still  holds  its  ground  in  Europe,  and 
large  quantities  are  exported  to  China  and  Japan.  On 
the  whole,  however,  despite  the  few  collections  of  shells 
on  a  cottager's  mantelpiece,  the  love  of  these  marine  pro- 
ductions has  died  out  far  more  than  the  previous  tastes. 

Coeval,  doubtless,  with  the  habit  of  gathering  these 
treasures  of  the  sea-shore  is  that  of  picking  up  bright- 
coloured  pebbles  or  crystals.  Of  this  we  have  already 
seen  numerous   examples,  and  further   repetition  w^ould 

Q 


242  THE  COLOUR-SENSE. 

only  fatigue  the  reader.  A  mere  brief  list  of  some  prin- 
cipal varieties  must  suffice — sucli  as  the  diamond,  ruby, 
sapphire,  topaz,  garnet,  carbuncle,  amethyst,  jasper, 
emerald,  beryl,  jacinth,  onyx,  opal,  and  turquoise  ;  marble, 
porphyry,  granite,  serpentine,  malachite,  jade,  fluor  spar, 
amber,  satin-stone,  agate,  alabaster,  lapis  lazuli,  quartz, 
and  bloodstone. 

The  use  of  decorative  metals  is  closely  bound  up  with 
that  of  the  preceding  class.  The  brilliancy  and  the  colour 
of  gold  and  silver  early  attracted  the  attention  of  primitive 
man.  Used  in  conjunction  with  the  precious  stones,  they 
compose  what  we  know  as  jewellery,  which  forms  one  of 
the  chief  decorative  appliances  of  all  savage  and  civilised 
races.  The  taste  which  begins  with  the  gold  neck  orna- 
ments of  the  barbaric  king,  culminates  in  our  own  jewel- 
lers' shops,  our  regalia,  our  gold  and  silver  plate,  our  city 
maces,  our  military  uniforms,  our  ecclesiastical  ornaments, 
and  our  Albert  Memorials.  Here,  again,  it  is  interesting 
to  note  the  connection  of  state  ceremonial  and  religious 
ritual  with  the  earliest  decorative  devices  of  primitive 
chieftains. 

All  the  objects  which  we  have  hitherto  examined  agree 
in  one  particular — they  are  self-coloured.  Man  finds  them 
as  he  uses  them,  and  transfers  at  once  to  the  brilliant 
gewgaws  the  taste  which  was  developed  upon  the  bright- 
hued  fruits.  It  is  the  property  of  natural  colouration 
which  gives  to  some  of  them  their  special  value.  Flowers 
and  fruits,  besides  being  transitory,  are  common  and  univer- 
sal, and  so  they  are  only  prized  for  their  immediate  beauty. 
Feathers  and  shells,  though  more  permanent,  are  still  too 
easily  procured  to  rank  high  in  exchange  value.  But 
jewels  and  precious  metals,  besides  being  indestructible, 
are  naturally  rare,  and  cannot  be  artificially  multiplied ; 
so  that  their  value  is  proportionately  and  permanently 
great.  Yet  it  may  be  noted  that  their  aesthetic  rank  is 
not  so  elevated  as  that  of  flowers  or  even  of  beautiful 
feathers  (though  here  many  will  disagree),  partly,  perhaps, 


THE  ESTHETIC  VALUE  OF  COLOUR.  243 

because  of  the  strong  element  of  glitter  and  powerful  total 
stimulation,  but  still  more,  I  fancy,  because  the  economical 
value  has  vulgarised  them  hopelessly,  reducing  them  from 
the  level  of  beautiful  natural  objects  to  the  position  of 
mere  high-priced  baubles. 

The  class  which  we  have  next  to  examine,  however,  is 
that  of  materials  not  naturally  coloured,  but  artificially 
stained  or  dyed.  Man  at  length  progresses  beyond  the 
mere  passive  stage  of  aesthetics,  and  enters  upon  the  active 
career"  of  the  artist.  No  longer  content  simply  to  gaze 
with  pleasure  upon  the  fruits,  flowers,  birds,  butterflies, 
shells,  corals,  and  precious  stones  which  nature  has  beauti- 
fied beforehand  for  his  admiration,  he  begins  on  his  own 
account  to  increase  the  stock  of  coloured  objects  by  the 
application  of  pigment. 

^  Pigment  stands  in  the  same  relation  to  the  natural  taste 
for  colour  as  sugar  to  the  natural  taste  for  sweetness,  or 
artificial  essences  to  the  natural  taste  for  perfume. 

We  get  the  first  stage  of  this  active  process  in  tlie  use 
of  ochre,  chalk,  and  charcoal,  for  the  decoration  of  the  hair 
and  body.  These  pigments  represent  a  very  elementary 
form  of  painting,  because  in  their  case  a  friable  substance 
is  merely  applied  to  another  body,  so  that  small  fragments 
adhere  by  their  own  nature  or  by  simple  wetting.  The 
expression  of  vegetable  juices  gives  us  a  step  in  advance, 
as  in  the  case  of  woad,  indigo,  logwood,  and  the  like.  The 
dyeing  of  cloth  carries  us  still  further  on  the  upward 
march ;  and  the  discovery  of  mixed  pigments,  applied 
with  a  stamp  or  brush,  puts  a  culminating  touch  to  the 
process.  Dyeing  and  painting  revolutionise  the  whole 
environment  of  semi-civilised  man,  until  at  last,  if  the 
reader  will  cast  his  eye  around  the  room  in  which  he  sits, 
he  will  see  that  scarcely  an  object  can  be  found  in  it  which 
has  not  received  some  purely  decorative  addition  of  pig- 
ment, stain,  or  polish. 

Side  by  side  with  this  great  change  goes  the  discovery 
of  glass,  porcelain,  and  other  materials  which  imitate  the 


244  THE  COLOUR-SENSE. 

natural  colouring  of  precious  stones.  The  numerous 
changes  which  can  be  rung  upon  these  various  materials, 
together  with  pigments,  dyes,  and  textile  fabrics,  would 
demand  a  separate  history,  and  cannot,  therefore,  be  ade- 
quately treated  in  a  single  chapter. 

But  it  must  be  remembered  that  wdiile  mankind  have 
been  transferring  their  native  love  for  colour  to  these  new 
objects,  aud  exercising  their  sense  upon  these  artificial 
stimulants,  the  taste  must  have  been  widening  and  deep- 
ening from  day  to  day.  It  might  have  seemed  to  the 
reader  at  first  that  these  sesthetic  feelings,  derived  from 
a  remote  ancestry,  must  be  growing  perpetually  weaker 
with  the  lapse  of  time,  so  that  some  fear  might  arise  for 
their  iinal  obsolescence.  But,  really,  man  has  gone  on 
from  age  to  age,  surrounding  himself  more  and  more  with 
beautiful  flowers,  bright  clothing,  decorative  furniture, 
works  of  art,  and  all  other  exquisitely-coloured  objects,  so 
that  what  was  at  first  a  mere  passing  fancy  for  pebbles 
and  shells,  has  developed  at  length  into  a  perfect  neces- 
sity of  his  fully-evolved  nature.  As  an  able  writer  in 
the  '•  Eevue  Philosophique "  has  pointed  out,  even  the 
veriest  boor  would  now  feel  half  his  existence  cut  from 
under  him  if  the  whole  aesthetic  element  were  removed 
out  of  his  life. 

A  third  point  of  view  must  engage  our  attention  for  a 
while  before  we  quit  the  subject  of  the  sesthetic  value  of 
colour.  I  mean  the  gradual  progress  in  disinterestedness^ 
which  marks  the  evolution  of  the  sesthetic  feelings. 

The  starting-point  of  visual  aesthetics,  as  w^e  have 
already  seen,  is  the  appreciation  of  bright  colour  in  the 
fruits  which  form  the  common  food  of  the  original  species. 
A  close  connection  with  vital  function  is  here  obvious 
and  unmistakable.  The  simplest  transference  from  this 
primordial  pleasure  consists,  doubtless,  in  the  mere  tran- 
sient interest  in  brilliant  objects  of  the  nearer  environ- 
ment, such  as  flowers,  parrots,  or  butterflies.  Not  only 
the  quadrumana,  but  savage  or  uncultured  man  himself, 


THE  ESTHETIC  VALUE  OF  COLOUR.  2;5 

displays  little  interest  in  such,  intangible  and  distant 
manifestations  of  colour  as  the  rainbow  or  the  sunset. 
But  monkeys  are  reported  to  pull  to  pieces  handsome 
blossoms,  to  snatch  the  longer  feathers  from  unsuspecting 
birds,  and  to  dart  after  beautiful  butterflies  which  flit  past 
them  on  the  wing  in  the  brio-ht  sunlioht.  No  doubt  their 
interest  is  quite  as  momentary  as  that  of  the  child  who 
tears  out  the  ray-fiorets  of  a  daisy,  or  chases  a  Camber- 
well  beauty  across  the  meadow ;  yet  if  the  facts  as  com- 
monly related  be  really  true,  they  show  at  least  some 
slight  disinterested  love  for  colour,  inasmuch  as  coloured 
bodies  are  instinctively  selected  as  objects  of  passing 
pursuit,  while  green  leaves  or  brown  insects  attract  little 
or  no  attention. 

The  monkey,  however,  goes  no  further  in  his  aesthetic 
career  than  this  first  simple  step — for,  of  course,  we  must 
count  the  phenomena  of  sexual  selection  as  manifesta- 
tions of  purely  interested  feeling.  But  man  proceeds  to 
employ  the  objects  wdiich  he  collects  as  means  for  his 
own  personal  decoration.  The  adornment  of  the  body 
thus  constitues  the  second  stage  of  disinterested  aesthetic 
progress.  Flowers  stuck  into  the  rude  head-dress,  or 
woven  into  festoons  for  wreaths  and  girdles,  form  one  of 
the  earliest  and  most  natural  ornaments.  But  beautiful 
as  these  simple  articles  of  dress  must  always  be,  they  fade 
too  soon  for  permanent  use.  Accordingly,  shells,  corals, 
pebbles,  precious  stones,  feathers,  and  furs  supersede  them, 
where  obtainable,  as  decorative  appliances.  The  first 
function  of  pigment  is  for  daubing  the  hair  and  body; 
while  tattooing,  originally  a  form  of  subordinative  mutila- 
tion, grows  at  last  into  a  mere  aesthetic  practice.  As 
knowledge  and  arts  increase,  rude  textile  fabrics  come  into 
use,  and  being  dyed  or  stained  with  red,  yellow,  and  blue, 
form  personal  adornments  for  the  savage  chief.  Of  course, 
the  whole  original  object  of  dress  was  that  of  decoration, 
the  ideas  of  warmth  and  decency  only  coming  in  as  after- 
thoughts at  a  later  period.    Amongst  the  lower  races,  men, 


246  THE  COLOUR-SENSE. 

not  women,  monopolise  the  handsomest  costumes,  which 
are  worn  as  marks  of  distinction  rather  than  as  purely 
aesthetic  adjuncts.  Here,  once  again,  we  note  that  the 
employment  of  colour  in  male  dress  survives  amongst  our- 
selves mainly  in  connection  with  military,  ecclesiastical, 
and  governmental  etiquette. 

Yet  even  the  humming-birds  have  passed  beyond  this 
second  stage  of  disinterested  aesthetic  feeling,  and  reached 
the  third  step,  which  we  have  next  to  consider ;  for,  as  Mr. 
Gould  tells  us,  they  decorate  their  nests  with  pretty  bits 
of  lichen  or  brilliant  feathers,  interwoven  with  the  mate- 
rials of  the  outer  wall.  Much  more  have  our  old  friends 
the  bower-birds  overstepped  this  higher  limit,  by  posi- 
tively instituting  what  may  be  described  as  Assembly 
Rooms,  adorned  with  all  kinds  of  coloured  or  shining 
objects.  Obviously,  the  ornamentation  of  your  home  is 
one  degree  more  disinterested  than  the  ornamentation  of 
your  own  person,  and  that  of  your  temples  or  public  build- 
ings, one  degree  more  so  than  that  of  your  home.  Both 
these  steps  are  soon  taken  in  the  course  of  human  evolu- 
tion. The  ncOToes  of  the  Niojer  stain  the  exterior  of  their 
huts  with  blue  and  white ;  while  the  people  of  High  Asia 
commonly  paint  theirs  with  grotesque  figures.  Amongst 
our  own  houses,  external  painting  is,  of  course,  very 
common,  especially  in  countries  where  wood  is  largely 
employed  as  a  building  material.  But  internal  decoration 
carries  us  a  step  higher,  because  it  does  not  bear  the  same 
impress  of  mere  ostentatious  display;  it  shows  more 
ingrained  personal  aesthetic  sensibility,  and  less  love  of 
admiration  at  the  hands  of  others.  The  West  Indian 
negroes  dress  in  very  bright  colours,  and,  on  the  whole, 
with  admirable  taste — the  brilliant  hues  setting  off  with 
effect  the  natural  darkness  of  their  skin — but  they  seldom 
or  never  do  anything  toward  the  decoration  of  their  huts, 
which  are  mere  square  blocks  of  mud  wall,  lightly  roofed 
with  palm-thatch.  A  step  higher  up,  the  West  African 
negroes  paint  their  huts  externally,  while   inside   they 


THE  AESTHETIC  VALUE  OF  COLOUR.  247 

remain  mere  brown  and  dirty  hovels.  But  the  cultivated 
civilised  man  thinks  more  of  surrounding  himself,  under 
his  own  roof,  with  beautiful  and  ennobling  works  of  art, 
than  of  making  a  boastful  external  show  before  the  eyes 
of  his  neighbours. 

Under  the  same  heading,  we  may  notice  the  cultivation 
of  flowers  in  gardens  and  windows.  This  practice  exhibits 
a  considerable  advance  upon  the  mere  casual  taste  for 
picking  pretty  blossoms,  and  also  upon  the  collection  of 
naturally-grown  flow^ers  for  personal  decoration.  It  testi- 
fies to  aesthetic  forethought,  and  gives  room  for  immense 
disinterested  developments  of  aesthetic  feeling.  Gardens 
of  more  or  less  rude  construction  are  found  very  far  down 
in  the  scale  of  humanity,  and  they  continue  to  be  objects 
of  solicitude  up  to  the  very  highest  level  of  civilisation. 

The  habit  of  keeping  birds  (especially  those  of  bright 
plumage,  like  parrots,  cockatoos,  and  peacocks)  as  domestic 
pets,  deserves  a  passing  notice  in  the  same  connection. 
How  low  down  in  the  scale  of  civilisation  this  practice 
may  extend  I  cannot  say;  but  I  observe  that  Captain 
Moresby^  mentions  it  as  prevailing  among  the  savage 
Papuans. 

If  the  mere  common  savacie  decorates  his  own  little 

o 

hut  with  pigment,  skulls,  shells,  and  flowers,  much  more 
will  the  great  chief  gather  around  his  dwelling  these 
aesthetic  adjuncts,  and  others  of  higher  kind.  Only  kings 
in  Hawaii  were  permitted  to  use  the  feathers  of  the 
Melithreptes,  from  which  the  royal  robes  were  woven. 
Purple  has  always  been  a  pcculium  of  kingship,  and  the 
palace  is  naturally  thought  of  as  a  finer  and  more  brilliant 
building  than  the  hut  or  house  of  a  subject.  Even  the 
veriest  savages  have  distinctions  of  dress  and  decoration 
for  their  chiefs ;  and  when  we  come  to  the  royal  abodes 
of  Egypt,  Assyria,  Mexico,  and  Peru,  we  see  at  once  how 
large  a  share  monarchy  has  borne  in  the  development  of 
artistic  handicraft,  which,  of  course,  entails  a  corresponding 

1  Discoveries  in  New  Guinea,  p.  219. 


248  THE  COLOUR-SENSE, 

development  of  the  aesthetic  feelings.  Solomon's  house 
and  ivory  throne/  as  well  as  his  "  apes  and  peacocks,"  ^ 
will  immediately  occur  to  the  Biblical  student.  If  we 
trace  this  influence  down  through  history,  we  shall  find 
that  princes  have  always  been  the  great  patrons  of  fine 
art,  and  that  painting  in  particular  has  been  almost 
entirely  fostered  under  the  protection  of  monarchs  and 
aristocracies.^  But  these  royal  decorations  react  upon 
the  popular  taste,  and  finally  afford  new  outlets  for  the 
disinterested  aesthetic  sentiment  of  the  people.  Hitherto, 
the  sense  of  beauty  has  been  more  or  less  linked  with  the 
feeling  of  proprietorship :  beyond  this  line  it  gains  more 
and  more,  with  every  step,  in  abstractness  and  remoteness 
from  the  personality  of  the  individual. 

Eeligion,  however,  does  still  more  for  the  aesthetic 
sentiment  than  even  governmental  adjuncts.  If  the 
house  of  the  chief  receives  exceptional  decoration,  much 
more  does  the  house  of  that  deified  ghost-chief,  the  god. 
Wherever  we  look,  w^e  see  that  all  the  resources  of  art, 
infantile  or  full-grown,  are  most  fully  employed  in  the 
service  of  religion.  Painting,  sculpture,  music,  the  thou- 
sand minor  arts  of  decoration  and  dress,  all  combine  to 
do  honour  to  the  gods  of  the  country.  From  the  West 
African  fetish,  through  the  Polynesian  shrines,  the  Indian 
topes,  the  Chinese  pagodas,  the  Mexican  and  Peruvian 
temples,  the  mysterious  colonnades  of  Egypt,  the  massive 
architecture  of  Babylon  or  Nineveh,  the  Hellenic  Parthe- 
nons,  the  Italian  Capitols,  to  the  modern  mosques  of 
Islam  and  the  towering  cathedrals  of  Christendom,  we 
find  the  highest  artistic  handicraft  of  every  age  and  race 
lavished  upon  the  dwelling-place  of  the  national  deities. 
The  few  traces  of  aesthetic  feeling  in  the  Hebrew  Scriptures 

1  I  Kings  vii.  ^  ibid.  x.  22.  as  a  curious  fact  tliat  had  it  not  been 

^  Thus  it  turns  out  that  (paradoxical  for  the  royal  parks  and  gardens,  Lon- 

as  it  must  at  first  sight  appear)  even  don  and  Paris  woidd  have  been  left 

kings  and  queens  are  not  without  their  almost    entirely    destitute    of    open 

ultimate  uses.    It  has  often  struck  me  breathing-spaces. 


THE  ESTHETIC  VALUE  OF  COLOdiRY.      251 

are  connected  with  the  workmanship  of  the  Tabern-at  a 
the  Temple,  and  the  hieratic  dress.  I  have  pointed  011  ^ 
elsewhere  ^  how  large  a  part  the  religious  sentiment  has 
borne  in  the  genesis  of  the  sublime :  it  must  here  suffice 
thus  briefly  to  hint  at  the  impetus  which  it  has  given  to 
the  kindred  feeling^  of  the  beautiful.  Whether  we  look  at 
the  endless  painted  images  of  Karnak  or  at  the  stained 
windows  of  Salisbury,  we  must  equally  recognise  the 
enormous  influence  of  relidon  in  the  OTOwth  of  disinterested 

o  o 

gesthetic  feelincr. 

The  remaining  steps  of  the  process  would  carry  us  too 
far  into  the  general  realm  of  aesthetics,  if  treated  in  full 
detail.  Enough  has  been  done  already  to  show  the  main 
course  of  evolution,  whereby  the  love  for  colour  becomes 
extended  and  divorced  from  the  personality  of  the  sentient 
mind.  The  final  step,  it  seems  to  me,  is  taken,  when  we 
arrive  at  the  pure  love  of  colour  in  nature  for  its  own 
sake,  the  love  which  draws  the  cultivated  man  to  gaze 
with  delight  upon  the  autumn  hues,  the  rainbow,  the  sun- 
set clouds,  or  the  myriad  tints  of  sea,  and  sky,  and  plain, 
and  forest.  In  works  of  art,  so  many  additional  factors  of 
plot-interest,~of  admiration  for  imitative  skill,  or  of  critical 
appraisement,  enter  into  the  total  of  our  consciousness, 
that  we  can  hardly  analyse  our  feeling  into  its  simple 
constituents;  but  when  we  look  upon  the  crimson  and 
golden  hues  of  evening,  the  thrill  of  pleasure  which  echoes 
through  our  brain  represents,  I  believe,  almost  the  purest 
form  of  disinterested  love  for  mere  colour. 

1  See  "The  Origin  of  the  Sublime,"  in  "Mind"  for  July  1878. 


248  (    250    ) 


CHAPTER  XIII. 

THE   GROWTH    OF    THE   COLOUR-VOCABULARY. 

The  names  of  colours  are  abstract  words :  they  repre- 
sent an  attribute,  not  an  object.  Accordingly,  they  do 
not  belong  to  the  class  of  words  which,  form  the  voca- 
bulary of  young  children  or  of  primitive  men.  They 
arise  gradually,  during  the  course  of  human  evolution, 
personal  and  collective,  in  proportion  as  they  are  required" 
by  the  needs  of  the  individual  or  the  race.  A  child  of 
two  years  old  (or  a  little  more)  knows  very  well  the 
names  of  grapes,  strawberries,  and  oranges  ;  but  for  purple, 
crimson,  and  orange  as  a  colour,  it  has  as  yet  no  appro- 
priate verbal  symbol.^  If  you  ask  it  what  it  calls  these 
things,  it  will  answer  at  once,  "glape,"  '' tlawbellie,"  or 
"  olage,"  as  the  case  may  be ;  but  if  you  ask  it,  "  what 
colour  is  this  ? "  it  has  no  answer  ready,  because  it  does 
not  even  comprehend  the  question. 

Intelligent  adults  who  have  received  a  philosophical 
education — or  rather,  an  education  in  philosophy — have 
grown  so  accustomed  to  the  conception  of  substance  as 
composed  of  attributes,  so  habituated  to  the  analytical 
mode  of  regarding  concrete  objects,  that  they  find  a  dif- 
ficulty in  realising  the  mental  state  of  the  unsophisticated 
human  being.  An  educated  man,  if  asked  to  describe  a 
grape,  would  answer,  "  It's  a  small,  round,  sweet,  purple 

^  I  am  not  speaking  here  by  guess-work,  but  stating  the  result  of  numerous 
actual  experiments. 


GROWTH  OF  THE  COLOUR-VOCABULARY.      251 

fruit,  which  grows  in  clusters  on  a  twining  vine ; "  l  but  a 
labourer  would  have  recourse  to  better  known  concrete  ob- 
jects, and  reply, "  It's  something  like  a  plum,  only  about  the 
size  of  a  cherry,  and  grows  in  bunches  the  same  as  currants." 
Or  again,  if  a  naturalist  discovers  for  the  first  time  a  new 
animal — say  an  argus  pheasant — he  will  minutely  charac- 
terise its  shape,  size,  colour,  external  appearance,  and 
internal  structure,  detailing  all  these  points  in  extremely 
abstract  language  ;  whereas,  a  countryman  who  goes  to 
the  Zoological  Gardens  will  simply  describe  it  as  "  be- 
tween a  peacock  and  a  guinea-hen."  In  every  case,  the 
average  intelligence  of  mankind  endeavours  to  grasp  an 
idea  by  means  of  concrete  realities.  Only  by  an  effort  is 
it  able  to  resolve  the  complex  whole  into  its  ultimate 
analytic  constituents. 

We  shall  fall  into  many  errors,  therefore,  if  w^e  insist 
upon  reading  the  simple  language  of  primitive  man  by 
the  light  of  our  developed  experience.  Evolution  for  ever 
impresses  upon  us  the  lesson,  that  if  we  would  be  good 
philosophers  we  must  forget  our  philosophy.  Thus,  the 
formal  logician  was  prepared  to  interpose  his  learned 
objection  just  above,  when  I  said  that  the  names  of 
colours  are  abstract.  For  the  purposes  of  his  artificial 
system,  with  its  propositions  and  denotations  and  in- 
tensions, blue  and  green  are  concrete  terms.  I  have  no 
fault  to  find  with  the  expression ;  when  writing  logically, 
we  must  all  allow  the  truth  of  the  distinction.  But  from 
the  point  of  view  of  psychology,  every  word  which  does 
not  denote  a  concrete  thing  in  its  totality,  or  a  picturable 
action,  must   be   regarded    as  abstract.     While    general 

1  I  have  purposely  given  the  natu-  diameter,  round,  instead  of  spherical, 

ral  answer  of  an  ordinary,  well-edu-  and  siocet  as  a  symbol  of  the  compound 

cated,    non-botanical   speaker.      But  and    delicate    grape-flavour.      Then, 

see  how  absurdly  inadequate  the  de-  again,  we  have   no  information  whe- 

scription  really  is  !     Setting  aside  its  ther  it  is  a"  stone-fruit "  or  a  "  berry, " 

total  want  of   structural  detail,  and  and  whether  it  is  edible  or  poisonous- 

merely  regarding  it  from  a  practical  Yet  the   description   is  really  a  very 

point  of  view,  what  a  vague  expres-  good  one  as  descriptions  go. 
sion  is  small,  in  lieu  of  a  measured 


252  THE  COLOUR-SENSE. 

names  are  not  real  abstractions,  "because  they  describe  in- 
discriminable  individuals/  adjectives  are  real  abstractions, 
because  they  describe  a  single  property  viewed  in  isolation 
from  the  other  properties  of  the  objects  in  which  it  is  an 
element. 

The  names  of  colours,  then,  are  abstract  words  ;  but,  like 
all  other  abstracts,  they  necessarily  take  their  rise  from  a 
concrete.  A-^uinient^s^Bflexien-willr--shew-"as^ -th^^  the 
evolutiQn.ofdanguaga_(3q^iild_iiot-proGeedr-otherwase.  The 
earliest  names  must  be  names  of  thingjs  or  of  visible  and 
audible  actions.  These  must  afterwards  be  applied  to. 
other  like  things  or  to  similar  attributes,  by  slight  changes 
in  their  meaning.  Unless  primitive  man  in  the  search  for 
a  means  of  intercommunication  had  hit  upon  the  plan  of 
framing  a  conventional  word  to  express  an  abstract  idea — 
a  plan  obviously  itself  too  abstract  in  its  nature  for  adop- 
tion by  any  but  a  high  order  of  intelligence — he  must 
clearly  proceed  by  forming  new  words  out  of  the  old,  by 
likening  the  unnamed  to  the  nameable.  And  as  a  matter 
of  fact,  philological  analysis  shows  us  that  such  has  been 
the  actual  course  of  development — that  every  abstract 
word  can  be  ultimately  traced  back  to  a  root  of  extreme 
concreteness,  and  every  expression  of  attribute  can  be 
shown  to  belong  in  its  origin  to  a  definite  subject. 

It  would  be  easy  to  give  a  philological  analysis  of  the 
common  colour  names,  such  as  red,  green,  blue,  and  yellow, 
in  several  ancient  and  modern  languages,  which  would 
bear  out  the  truth  of  this  assertion ;  but  I  prefer  to  take 

^  I  have  no  room  here  for  the  dis-  "Papa;"    it  only  slowly  grows  to 

cussion  of  this  side-issue,  but  I  may  demarcate  the  actual  Papa  from  other 

just  point   out   in  passing  that  the  men.     We  recognise  meat  before  we 

word  man  is  not  in  practice  arrived  at  recognise  heef  and    mutton  ;  or   tree, 

(as  logicians  tell  us)  by  abstracting  before  oak  and  elm.    Nobody  knows 

from  the  various  individual  men  what  one  pin  or  one   <s.%%   from  another  ; 

is  common  to  each,  but  by  the  childish  they  are  thought  of  as  the  same  :  and 

mind  recognising  originally  a  number  if  we  are  shown  two  in  succession  or 

of  exactly  similar  units,  some  of  which  the  one  twice  over,  our  impressions 

it  afterwards  learns  to  discriminate,  are  absolutely  identical. 
A  child  at  first  regards  all  men  as 


GROWTH  OF  THE  COLOUR-VOCABULARY.      253 

examples  from  a  later  date,  and  to  show  the  origin  of  one 
or  two  very  new  expressions,  whose  meaning  is  too  plain 
to  admit  of  any  doubt.  Though  this  method  has  far  less 
appearance  of  learning  than  the  other,  it  carries  a  great 
deal  more  conviction  to  the  general  reader  i-fe  we  can^ 
e^^y  see  that  rose-coloured  is  directly  derived  from  the 
known  w^ord  and  the  known  concrete  object,  a  rose ; 
whereas  most  people  must  take  on  trust  the  origin  of  hrown 
from  an  Indo-European  verb  meaning  to  burn,  or  that  of 
the  heraldic  gules  from  a  Persian  word  glml,  which  desig- 
nates the  same  favourite  flower. 

Among  such  new  terms  of  undoubted  derivation,  we 
may  take  as  specimens  lilac,  lavender,  and  violet,  which 
are  borrowed  from  the  concrete  names  of  flowers;  and 
orange,  cherry,  ajyple-green,  which  are  borrowed  from  those 
of  fruits.  So,  too,  to  go  a  little  further  back,  we  have 
'pink  from  the  well-known  blossom ;  and  the  almost  obso- 
lete saffron,  a  favourite  colour-epithet  with  Elizabethan 
poets.  Again,  we  find  the  Erench  words  cerise,  mauve, 
and  4cru  in  common  use  among  drapers  and  their  lady- 
customers  ;  and  when  we  inquire  into  their  meaning,  we 
see  at  once  that  the  first  is  the  same  as  our  cherry^  the 
second  is  the  name  of  the  marsh-mallow,  and  the  third 
(literally  unUeached)  is  a  derivative  of  the  Latin  crudus  ; 
so  that  in  every  case,  when  we  go  back  a  little  Avay,  we 
see  that  the  abstract  colour-term  is  always  a  special 
application  of  a  very  concrete  primitive  object-name.       y 

i^act,  when  we  wish  to  express  a  hitherto  unnamea^ 
colour,  the  simplest  way  of  doing  it  is  to  take  an  object 
which  possesses  that  colour,  and  apply  its  title  a3  ana^^^ 
jective  to  the  thing  which  we  wish  to  describe./hAr^ar—- 
ticular  shade  of  very  light  yellow  has  no  distinctive  name 
at  a  particular  time  ;  but  we  must  call  it  something  for 
some  special  purpose,  and  so  we  think  of    its   nearest 
common  representative,  a  primrose.     Thenceforward,  the 
'new  name  becomes  an  adjective,  and  we  ask  naturally 
for  a  yard  of  primrose  ribbon.     Kow,  what  we  see  civil- 


254  THE  COLOUR-SENSE. 

ised  men  doing  to-day  under  our  own  eyes,  primitive  men 
did  centuries  ago,  when  they  framed  the  earliest  colour 
names.  ^It  would  seem  at  present  as  though  the  various 
terms  for  colours  might  be  divided  into  two  classes,  the 
truly  abstract,  such  as  Uite,  green,  yellow,  and  the  concrete 
used  abstractly,  such  as  lilac,  orange,  pink.  The  former 
class  appear  to  have  no  other  meaning  than  that  of  pure 
colour ;  while  the  latter  class  are  clearly  derived  from  the 
names  of  concrete  objects.  I  But  in  reality,  the  difference 
between  them  is  merely  one  of  time.  Abstract  colour 
terms  are  the  names  of  concretes,  whose  original  significa- 
tion has  been  forgotten. 

Yet  another  general  principle  of  vocabularies  must  be 
considered,  if  we  wish  rightly  to  comprehend  the  growth 
of  colour  names.  Words  arise  just  in  proportion  to  the 
necessity  which  exists  for  conveying  their  meaning.  For 
example,  to  take  the  specific  case  of  colours,  we  have  seen 
a  large  number  of  colour  terms  introduced  within  our  own 
memory,  because  the  hues  to  which  they  referred  had 
become  fashionable  as  dyes  for  dress  materials.  Such 
are  the  instances  of  mauve,  4cru,  solferino,  magenta,  and 
cardinal,  every  one  of  which  has  obtained  a  definite  name 
only  because  it  had  been  employed  in  the  drapery  trade. 
In  short,  we  invent  words  as  we  need  them. 

Armed  with  these  general  truths,  let  us  endeavour  to 
trace  out  the  origin  and  development  of  the  colour- 
vocabulary. 

Primitive  man  in  his  very  earliest  stage  will  have  no 
colour  terms  whatsoever.  He  will  speak  of  concrete 
objects  only,  and  when  he  uses  their  names  he  will  use 
them  as  implying  all  their  attributes.  He  does  not  need 
to  say  red  hlood,  for  all  blood  is  red ;  nor  green  leaves,  for 
all  leaves  are  green.  Blood  and  leaf  by  themselves  are 
quite  sufficient  for  every  one  of  his  simple  purposes. 

But  when  man  comes  to  employ  a  pigment,  the  name  of 
the  pigment  will  easily  glide  into  an  adjectival  sense. 
The  earliest  colour  terms  will  thus  be  produced.     I  learn 


GROWTH  OF  THE  COLOUR-VOCABULARY.      255 

from  Mr.  Whitmee  that  the  Samoans  use  three  kinds  of 
pigment — a  red  volcanic  earth,  a  molluscan  purple,  and  a 
turmeric ;  and  the  names  of  these  three  pigments  are 
applied  as  colour  terms.^  So,  too,  many  other  informants 
have  given  me  like  instances  with  other  races./  A  large 
proportion  of  our  own  colour  terms  are  derived  from  dyes 
or  pigments.  Such  are  crimson  (or  cramoisi)  from  the 
Arabic  karmesi,  the  kermes ;  ^  Termilion  or  vermeil,  from 
vermicidics,  because  it  was  supposed  to  be  the  product  of  a 
worm ; ^  gamhogefhovn  Cani]xidm,ilie-^lace_£>lita-export ; * 
indigo,  from  Spanish  indico,  the  Indian  dye ;  ^  and  saffron, 
from  the  common  English  plant. 

Moreover,  we  saw  that  red  is  the  earliest  colour  used  in 
decoration,  and  accordingly  it  is  the  earliest  colour  which 
receives  a  special  name^  This  fact  has  been  fully  brought 
out  by  the  researches  of  Geiger,  Magnus,  and  Mr.  Glad- 
stone ;  and  it  will  not  therefore  be  necessary  tp^  accumu- 
late further  proofs  in  the  present  volume.i^l'he  early 
prominence  of  red,  however,  has  left  some  cilrious  traces 
in  language,  as  well  as  in  art,  to  the  present  day,  which 
deserve  a  passing  notice  here.  Ssis-rthe  Indo-European 
dialects  contain  a  number  of  words  for  this  colour  from  a 
common  root — e-riitli-ros,  mdjeus,  russus,  ruadh,  roth,  red, 
rouge,  rolhio,  roux,  ruddy,  &c.^  while  there  is  no  such  wide- 
spread and  common  root  for  blue — cceruleus,  hlau,  azul — 

1  In  this  case  and  in  many  others,  the   case  of  the   Samoans  were  eJe, 
correspondents  have  kindly  supplied  2muli,  and  lenga  respectively.      Ac- 
me with  the  words  used  by  existing  cordingly  I  have  only  inserted  original 
savages,  or  by  early  historical  races,  words  in  the  text  when  they  belong 
such  as  the  Assyrians,  Hebrews,  and  to  languages  with  which  I  am  person- 
Peruvians  ;   and  I  might  have  given  ally   acquainted,   and   with   which   I 
a  certain   false  show  of  erudition  to  may  reasonably  expect  a  fair  famili- 
the  present  chapter  by  inserting  the  arity  on  the  part  of  the  reader, 
original  terms  as  given.     But  really  ^  Brachet,    Dictionnaire    Etymolo- 
the  important  point  for  our  purpose  gique  de  la  Langue  Fran^aise,  sub  voc. 
is   the   existence   of  the  words,    not  ^  Ibid.,  sub  voc. 
their  particular  form,  which  is  only  ■*  Isaac  Taylor,  Words  and  Places, 
valuable    for    philological    students,  p.  409. 
The  reader  would  be  none  the  wiser  ^  Ibid.,  p.  409. 
if  I  had  stated  that  these  forms  in 


256  •       THE  COLOUR-SENSE.  \ 

nor  for  green — chloros,  viridis,  griln}     AgaifiJ  we  English    i 
have  a  great  number  of  subordinate  colour  terms  in  popular    i 
use  to  express  the  various  shades  of  red,  such  as  crimson,    \ 
scarlet,  vermilion,  rosy,  and  j?m^,  besides  less  definite  words    i 
like  cherry,  ruddy,  russet,  carnation,  Hushing,  sanguine  or 
ensanguined,  ruby,  and  roseate;   but  we  have,  few  or  no ^^^ 
words   to  express   the  shades  of  green,1wniie  physicists 
have  had  to  introduce  the  conventional  terms  indigo  and 
violet  to  designate  the  widely  different  but  unnamed  hues   ; 
which  result  from  the  quickest  light- waves.     Once  more,  \ 
while  the  nouns  of  brightness  and  its  opposite  give  us  \ 
the  verbs  to  lighten  and  to  darken,  to  whiten  and  to  hlachen,   \ 
and  while  the  primitive  art- colour,  red,  gives  us  the  verb   ! 
to  redden,  we  have  no  such  words  in  our  lancruaoje  as  to 
Muen  and  to  greenen.      And  it   is  a  significant  fact,  as  \ 
regards  the  aesthetic  position  of  green,  that  whereas  the 
use  of  "  blue  "  in  laundries  has  given  rise  to  a  technical 
verb  of  washerwomen,  to  blue,  we  have  absolutely  no  verb 
meaning  "  to  green  "  or  "  to  viridise."     Finally,  the  mixed 
colours,  orange  and  purple,  into  which  red  enters  as  an 
element,  have  separate  popular  names,  but  no  other  mixed 
colours  have  any  but  technical  designations;  and  while 
these  red-like  words,  with  yellow,  the  adjunct  of  red,  yield 
us  the  verbs  to  purple,  to  crimson,  to  encarnadine,  to  en- 
saffron,  and  so  f  orth,^  I  cannot  call  to  mind  a  single  similar 
expression  with  reference  to  the  less  refrangible  rays. 
/During  the  period  or  stage  in  which  red  forms  the  main 
or  only  decorative  colour,  red  alone  has  a  conventional  or 
abstract  name.     All  other  hues  are  spoken  of  by  com- 
parison with  well-known  objects,  y  It  is  not  the  habit  of 
the  early  mind  to  refer  to  the  sky  as  blue,  or  the  leaves  as 

1  Curtius,  however  ("  Griecliisclie  the  HelleniG  and  Italian  race  from 

Etymologie,"  sub  voc),  identifies  the  their  Aryan  ancestors, 

roots  of  chloros  and  viridis.     I  must  ^  j^  should  be  added,  however,  that 

almost  confess  to  a  little  scepticism  ;  these  words  are  largely  due  to  the 

but  the  identification,  if  true,  would  special  poetical  effectiveness  of  red, 

show  that  green  was  discriminated  concerning  which  more  hereafter, 
and  named  before  the  separation  of 


GROWTH  OF  THE  COLOUR-VOCABULARY.      257 

green;  on  the  contrary,  it  speaks  of  blue  things  as  "sky- 
faced  "  (ccendeus),  and  of  green  things  as  "  sprout-like " 
{viridis,  connected  with  virere  ;  griln,  green,  connected 
with  groiv).  The  primitive  man  would  no  more  think 
of  saying  that  the  sky  was  sky-faced,  or  the  leaves  leaf- 
like, than  we  should  think  of  talkinsj  about  an  oranQ;e 
oranc^e,  or  a  lilac  lilac. 

But  so  soon  as  blue  becomes  a  recognised  art-colour, 
either  through  the  use  of  pigments  or  of  decorative  jewels, 
a  name  for  blue  springs  up.  One  of  the  commonest  in 
Europe  is  that  of  azure,  azur,  or  azul,  derived  from  the 
Persian  Idzur,  lapis  lazuli.^  "We  have  already  seen  that 
this  stone  was  very  early  imported  from  the  east,  and  it 
was  natural  that  it  should  give  a  name  to  the  hue  in  ques- 
tion, because  it  was  largely  employed  for  artistic  purposes. 
Emerald  and  turquoise  are  similarly  used  at  the  present  day 
to  designate  various  shades  of  green. 

At  this  second  or  red-blue  stage,  the  word  for  blue  seems 
often  to  be  applied  also  to  green.  This  is  not  surprising 
when  we  recollect  how  very  little  difference  really  exists 
between  these  two  colours.  Indeed,  I  am  convinced  that 
we  only  have  separate  names  for  them  at  all  because  the 
commonest  green  in  nature,  that  of  foliage,  and  the  com- 
monest blue  in  nature,  that  of  the  seldom-seen  open  sky, 
are  so  very  wide- spread  and  so  much  more  strikingly 
different  from  one  another  than  most  blues  and  screens. 
But  if  we  look  at  a  turquoise,  it  is  very  hard  to  say 
whether  we  should  assign  it  to  the  former  or  the  latter 
colour ;  while  the  sea  is  just  as  often  the  one  as  the  other. 
The  original  assumption  of  some  natural  object  on  the 
borderland  between  the  two  as  the  concrete  name-standard 
would  quite  sufficiently  account  for  the  common  confusion 

1  The  dropping  of  the  initial  I  is  iiarar?^^;  Arabic,  ndrar?/), "or  the  con- 
probably  due  to  its  being  mistaken  for  verse  instances  of  a  neivt  for  an  eft,  le 
the  definite  article — Vazur.    The  ana-  lierre  for  Vicrre  [hcdera)  will  occur  to 
logous  cases  of  an  adder  for  a  nadder,  all  philological  readers, 
and  un  orange  for  un  narange  (Spanish, 


2  58  THE  COLOUR-SENSE. 

between  tliem  in  language.  As  a  matter  of  fact,  Mr. 
Whitmee  informs  me  that  (the  word  for  bine  in  Samoan  is 
literally  sea-colour.  The  Welsh  use  glas  indiscriminately 
for  both ;  and  the  Assyrians,  according  to  Mr^-Sayce, 
described  green  as  either  blue  or  yellow ;  bttt-we^naw  in 
eaclHGas©- tlmt  the  tjolours  theffiffelTes-wer^^^-are-aGurately 
distiaguished.  The  Quiche  Indians  had  also  one  word,  rax, 
for  green  and  bluepk  y^4h€re-£an j3eJittlfi_dQubtLof  their 
prpj)©£LpfLree^tions.  /  I  believe  the  same  explanation  must 
be  offered  of  the  alleged  fact  that  the  Burmese  confuse 
these  two  central  colours ;  but  I  have  not  been  able  my- 
self to  examine  Bastian's  account,  and  the  gentlemen  in 
Burma  to  whom  I  addressed  inquiries  on  the  subject  did 
not  reply  to  my  circulars.  At  any  rate,  in  Burmese 
works  of  art,  blue  and  green  are  acurately  discriminated, 
and  blended  with  great  taste.  Certainly,  Professor 
Blackie  showed/  at  a  meeting  of  the  Eoyal  Society  of 
Edinburgh,  that  the  Highland  Scots,  who  call  sky  and 
grass  both  gorm,  could  perfectly  discriminate  bd^ween  the 
two  colours  when  tried  by  practical  tests^  It  may 
be  added  that  certain  hues  which  we  ordinarily  class 
roughly  together  as  reds,  for  instance  that  of  bricks  and 
that  of  some  light  pink  geraniums,  are  quite  as  far  apart 
from  one  another  in  consciousness  as  the  green  of  the 
eraerald  and  the  blue  of  the  sapphire.      j 

(^Yellow  generally  takes  its  first  name  from  gold.  Aureus 
is  the  common  Latin  epithet,  and  golden  hair  still  passes 
muster  in  everyday  colloquial  English.  Yon  Bezold  has 
shown  that  yellow  seldom  enters  into  decorative  art  except 
in  a  metallic  form,  and  that  it  never  rises  to  the  same 
distinct  aesthetic  prominence  as  red,  green,  and  blue.^  \ 

Green,  above  all  other  colours,  has  few  names  derived 
from  pigments,  because  it  is  so  seldom  employed  for 
decorative  purposes.     Most  of  its  designations  are  directly 


1  Sclierzer's  Ximenez,  p.  15,  note. 
2  Theory  of  Colours,  American  translation,  pp.  138,  181,  194. 


GROWTH  OF  THE  COLOUR-VOCABULARY.      259 

derived  from  grass  or  leaves  ;  the  remainder  belong  origi- 
nally to  fruits,  to  the  sea,  or  to  precious  stones. 

And  now  we  have  reached  the  point  in  the  development 
of  the  colour-vocabulary  at  which  most  semi-civilised 
nations,  all  children,  and  the  mass  of  uneducated  adults, 
always  remain.  Six  colours  are  commonly  recognised  by 
the  popular  mind — black  and  white,  red  and  blue,  green 
and  yellow.  The  first  pair,  of  course,  are  merely  words 
for  the  total  beam  and  its  negation ;  the  second  pair  form 
the  earliest  aesthetic  analytic  colours ;  and  the  third  com- 
plete the  ordinary  differentiation.  Add  grey  and  brown 
for  the  intermediate  or  muddily-mixed  shades,  and  we 
have  the  full  colour- vocabulary  of  everyday  life.  Even 
the  educated  only  speak  of  scarlet,  crimson,  lilac,  and 
purple  under  exceptional  circumstances,  as  in  literary 
composition  or  for  technical  purposes ;  but  to  the  mass  of 
mankind  these  lesser  distinctions  of  language  are  wholly 
unknown. 

Heraldry  has  stereotyped  this  conception  of  colour  in 
its  set  language  of  or  and  argent ;  gules,  azure,  and  ixrt ; 
and  sahle.  Here  we  have  two  metallic  colours,  those  of 
gold  and  silver;  and  four  non-metallic,  black,  red,  blue, 
and  green.  Of  the  latter,  one  name,  gules,  is  of  oriental 
origin,  and,  doubtless,  points  to  some  imported  Arabic 
pigment  (perhaps  vermilion) ;  one,  azure,  is  also  oriental, 
and  has  been  already  explained;  the  third,  vert,  is  Latin 
and  imitative ;  while  the  fourth,  salle,  is  derived  from 
zibellino,  sihelino,  or  siberino,  the  Siberian  fur.^  The  only 
compound  colour  known  in  heraldry  is  puiyitre,  while 
rair  and  ermine  are,  of  course,  mere  names  of  light  and 
shade  in  material. 

Tfee  ^further  differentiation  of  the  colour-vocabulary 
depends,  as  before,  upon  the  practical  needs  of  intercom- 
munication. I-fe4sr-s^^rc[oj,roloped  amung'tbrocr  clae^oo  of 
ps£»ec:s.  ^The  fa^class  i^S3a*-of  dyers,  drapers,  milliners, 

1  Isaac  Taylor,  Words  and  Places,  p.  415. 


26o  THE  COLOUR-SENSE. 

and  others  who  have  to  deal  with  coloured  articles  of 
clothing ;  their  vocabulary  includes  numerous  words,  such 
as  cherry,  cerise,  lavender,  lilac,  mauve,  solferino,  magenta, 
ecru,  p7'i7nrose,  and  cardinal,  besides  purely  technical 
names  like  Paris-in-flames.  As  might  be  expected  from 
the  usual  course  of  fashion,  a  large  proportion  of  these  are 
French.  N  The  second  class  includes  painters  and  other 
artists,  whose  colour-vocabulary  consists  largely  of  pig- 
ment names,  such  as  lake,  madder,  ultramarine,  carmine, 
Prussian  blue,  gamboge,  and  ochre.  The  third  class  is  that 
of  scientific  physicists,  whose  language  comprises  terms 
like  cyanogen-blue,  carnation,  indigo,  apple-green,  and 
sulphur-yellow.  It  may  be  added  that  the  introduction  of 
fresh  pigments  from  time  to  time  produces  a  direct  result 
in  enlarging  one  or  other  of  these  various  lists.  Thus,  the 
common  use  of  aniline  dyes  at  the  present  day  has  given 
rise  to  a  considerable  number  of  new  colour-terms. 

Furthermore,  special  technical  colour- words  are  used  in 
restricted  senses  as  applied  to  animals  or  other  objects  by 
different  trades.  Thus  the  names  chestnut,  bay,  sorrel,  and 
roa7i  are  only  used  of  horses ;  while  black,  ivhite,  Q'^^y,  ^^d 
cream-coloured  are  employed  with  specialised  significa- 
tions of  the  same  animals.  Cats  claim  a  monopoly  of 
tortoise-shell ;  and  tan  (in  the  phrase  black  and  tan)  forms 
the  peculiar  property  of  terriers.  Hair  alone  is  auburn, 
ajid  only  eyes  are  hazel. 
>o  ^  I  It  may  be  interesting,  before  we  pass  away  from  this 
'  part  of  our  subject,  to  give  a  brief  formal  classification  of 
the  various  concrete  origins  from  which  abstract  colour- 
adjectives  have  been  derived.  I  shall  take  my  examples 
only  from  the  commonly-known  English  words. 

Two  main  classes  may  be  distinguished  —  the  Pig- 
mentary and  the  Metaphorical. 

Pigmentary  colour-names  fall  under  three  heads.  First, 
the  material — as  vermiliooi,  crimson,  saffron,  indigo;  second, 
the  local — as  gamhoge,  Prussian  blue.  Par  is  green ;  third,  the 
conventional  or  artificial — as  magenta,  solferino,  cardinal. 


GROWTH  OF  THE  COLOUR-VOCABULARY.      261 

The  last-named  head  is  quite  modern,  and  of  slight  philo- 
logical value.  It  belongs  to  the  conscious  stage  of  word- 
making. 

Metaphorical  colour-names  fall  under  four  heads.  First, 
elemental — as  shy-Uue,  sea-green,  muddy.  Second,  vegetal — 
as  green,  from  foliage ;  as  pink,  molet,  rose,  lavender,  prim- 
rose, lilac,  from  flowers ;  as  orange,  cherry,  chestnut,  hazel, 
from  fruits.  Third,  mineral — as  golden,  silvery,  azure,  sap- 
phire, rioby,  emerald,  turquoise,  amethyst,  amber,  and  jetty  ; 
with  which  we  may  fairly  class  certain  animal  epithets, 
such  as  coral,  ivory,  and  pearly.  Fourth,  miscellaneous — 
as  sable,  sanguine,  snowy,  chocolate.  } 

And  now  we  must  pass  on  £0  a  second  question,  the 
reason  for  the  great  vagueness  of  all  colour  terms. 

I  believe  the  solution  of  this  difficulty  is  to  be  found  in 
the  nature  of  the  colour  sensations  themselves.  They  are 
nowhere  clearly  marked  off  from  one  another  by  definite 
lines.  The  solar  spectrum  contains  an  infinite  gradation 
of  hues,  each  of  which  fades  into  its  neighbour  by  im- 
perceptible degrees.  It  is  impossible  to  name  them  all, 
because  their  number  is  really  incalculable.  Hence  we 
are  reduced  practically  to  inventing  names  for  the  most 
prominent. 

A  glance  at  the  other  senses  wiU  throw  much  light 
upon  the  present  problem.  In  taste,  we  distinguish  a 
fairly  large  number  of  sensations  by  separate  names — 
sweet,  bitter,  pungent,  sour,  acrid,  and  so  forth;  but  we 
have  no  separate  word  for  the  flavour  of  a  peach,  a  straw- 
berry, and  a  grape.  We  refer  to  them  by  the  concrete 
name  of  the  object  as  a  whole,  just  as  primitive  man  does 
with  the  coloui^s.  In  smell,  we  have  even  a  smaller 
number  of  distinctive  terms,  for  we  only  speak  of  them 
as  sweet  or  stinking ;  and  these  words  refer,  not  to  the 
intelligible  qualities  of  the  scent,  but  simply  to  its  emo- 
tional aspect.  In  hearing,  we  generally  employ  the  two 
expressions  high  and  low,  or  their  equivalents,  treble  and 
bass.     But  here  we  have  elaborated  for  special  technical 


262  THE  COLOUR-SENSE. 

purposes  a  far  more  accurate  and  quantitative  nomen- 
clature ;  a  nomenclature  infinitely  superior  to  that  of  any 
other  sense,  not  excepting  the  sense  of  colour.  The  divi- 
sion of  the  audible  gamut  into  octaves  and  notes,  further 
divisible  into  semitones,  and  for  very  discriminative  ears 
into  minor  fractions,  down  to  one-sixty-fourth  of  a  tone, 
enables  us  exactly  to  express  in  language  the  very  minu- 
test possible  varieties  of  sensation.  This  admirable  system 
of  nomenclature  is  rendered  practicable  by  the  peculiar 
constitution  of  the  ear,  and  by  its  special  adaptation  to 
the  regular  harmonic  intervals. 

In  sight,  however,  no  such  minute  discrimination  is 
possible.  We  can  indeed  divide  straight  lines  into  inches, 
half-inches,  and  eighths-of-an-inch ;  while  the  microscope 
further  enables  us  to  discriminate  decimals,  hundredths, 
and  so  forth,  down  to  extremely  minute  fractions.  But 
in  colour  our  eye  is  not  fitted  for  noting  at  once  the 
relative  distance  of  rays  in  the  spectrum,  as  our  ear  is 
fitted  for  notinfy  the  relative  distance  of  tones  in  the 
gamut.  Accordingly,  we  must  have  recourse  to  some 
artificial  system. 

Such  a  system  was  proposed  by  Chevreul  in  his  "Expose 
d'un  moyen  de  definir  et  de  nommer  les  couleurs  d'apres 
une  methode  rationale  et  experimentale ; "  ^  but,  unfortu- 
nately, that  great  chemist  took  for  his  basis  the  mixture  of 
pigments,  not  that  of  rays;  ^  and  his  method  is  consequently 
incorrect  and  insufficient. 

Another  plan,  in  common  use  amongst  physicists,  is  to 
designate  the  colours  by  their  proximity  to  one  of  the 
lettered  lines  in  the  solar  spectrum.  Thus  cyanogen-blue 
may  be  approximately  defined  by  saying  that  it  lies  a 
little  to  the  violet  side  of  the  line  F.     But  this  plan  is,  of 


1   Memoires     de     I'Academie     des  Helmlioltz's  classical  work  on  "  Phy- 

Sciences,  vol.  xxxiii.,  1861.  siological  Optics."  The  English  reader 

-  For  an  explanation  of  this  cardinal  will  find  a  lucid  resume  of  the  ques- 

distinction,  too  fundamental  for  ex-  tion  in  Professor  Tyndall's  little  book 

position  in  the  present  volume,  see  "On  Light." 


GROWTH  OF  THE  COLOUR-VOCABULARY.      263 

course,  too  indefinite  and  too  little  numerically  accurate 
for  scientific  use. 

The  only  perfect  method  would  consist  in  an  artificial 
division  of  the  solar  spectrum  into  a  number  of  equal 
parts,  say  one  hundred,  and  the  invention  of  a  separate 
name  for  each  such  hundredth  part.  This  system  has 
been  partially  carried  out,  though  in  a  very  complicated 
manner,  in  Lambert's  colour-cone,  adopted  as  a  basis  by 
Helmholtz  and  Clark  Maxwell.  The  only  further  modifi- 
cation required,  is  that  of  an  extended  numerical  nomen- 
clature. 

Before  we  go  on  to  examine  the  application  of  the 
general  principles  here  laid  down  to  the  special  cases  of 
the  Hebrews  and  the  Homeric  Akhaians,  adduced  by  Dr. 
Magnus  and  Mr.  Gladstone,  it  may  be  worth  while  to 
glance  briefly  at  the  special  poetical  effectiveness  of  the 
colour-vocabulary.  As  the  authors  of  the  Akhaian  epics, 
and  of  many  among  the  Hebrew  books,  were  themselves 
poets,  the  use  of  colour  terms  by  other  poets  may  help 
us  to  estimate  more  correctly  the  true  value  of  the 
evidence  in  their  cases. 

Eed  is  pre-eminently,  and  beyond  all  comparison,  the 
poetical  colour.  It  is  applied  to  every  object  which  by 
any  straining  of  courtesy  can  possibly  be  conceived  as 
possessing  it ;  and  it  is  often  attributed  to  other  objects 
which  have  no  claim  whatsoever  to  the  title.  Thus  we 
have  red  gold,  red  lions,  red  right  hands,  red  kings,  the 
red  Douglas,  and  even  red  wrath.  The  great  red  sun 
sinks  nightly,  amid  red  clouds,  into  the  red  waters  of  the 
sea.  Eosy- fingered  dawn  spreads  crimson  glories  over  the 
empyrean ;  the  scarlet  flush  of  eventide  encarnadines  the 
fiery  sky.  A  great  many  reasons  conspire  to  produce  this 
effect.  In  the  first  place,  red,  as  we  have  abundantly 
seen,  is  the  most  universally  pleasing  of  all  colours.  Then 
again,  it  was  the  first  colour  employed  in  art-workman- 
ship, and  so,  as  Mr.  Gladstone  graphically  puts  it,  "  got 
the  start"  of  all  the  others.     This  further  secured  it  a 


264  THE  COLOUR-SENSE. 

certain  poetical  prescriptiveness,  especially  as  a  stock 
epithet  in  some  well-known  conjunctions,  like  those 
noted  above.  Finally,  its  special  use  as  an  adjunct  of 
royalty  or  state  ceremonial  gives  it  a  peculiar  claim  to 
poetical  use. 

N'ow,  I  am  not  a  great  believer  in  that  system  of  word- 
counting  which  is  so  favourite  a  device  with  Mr.  Glad- 
stone. It  appears  to  me  a  fallacious  and  illegitimate 
application  of  seemingly  rigorous  statistical  methods,  for 
the  value  of  the  word  can  never  be  properly  appreciated 
apart  from  its  context.  Nevertheless,  in  order  to  meet 
the  enemy  with  his  own  weapons,  I  have  counted  up 
all  the  colour-epithets  in  Mr.  Swinburne's  "  Poems  and 
Ballads,"  a  volume  which  I  have  purposely  selected, 
because  it  represents  the  spirt  of  traditional  poetry  in  its 
purest  form.  I  find  the  results  to  be  as  follows : — The 
word  red  occurs  in  all  151  times,  together  with  rosy,  crim- 
son, once  each,  and  sanguine,  ruddy,  scarlet,  twice  each : 
total  of  the  pure  red  epithets,  159.  Ze/Zo?^  is  mentioned 
13  times,  ^(X2^/'7i?/ once ;  but  the  more  poetical  word  gold 
numbers  113  repetitions,  and  golden  16:  total  of  the 
yellow  epithets,  143.  Purple  comes  in  for  23  notices. 
Grand  total  of  red-end  epithets,  325.  On  the  other  hand 
hlue  occurs  25  times,  and  violet  once;  total,  26.  Green 
obtains  mention  in  86  places.  Total  of  the  violet-end 
epithets,  no.  The  only  other  colour  term  is  Irown,  em- 
ployed 10  times.  Now,  I  acknowledge  that  this  is  an  ex 
parte  statement,  for  three  reasons :  I  have  reckoned  the 
word  gold,  which  is  sometimes  a  noun  and  sometimes  an 
adjective,  as  though  it  were  always  the  latter;  I  have 
counted  pi6?'^Ze  as  a  red-end  word,  though  it  miglit  equally 
claim  to  belong  to  the  violet ;  and  I  have  clubbed  together 
red  and  yellow.  But  Mr.  Gladstone  also  makes  ex  parte 
statements,  and  mine  seem  to  me  much  more  justifiable 
than  his.  For  gold  is  undoubtedly  a  favourite  word  in 
poetry,  largely  on  account  of  its  colour  and  glitter  ;  purple 
undoubtedly  owes  its  effectiveness  to  its  red,  not  to  its 


GROWTH  OF  THE  COLOUR-VOCABULARY.      265 

blue  element ;  and  the  yellow  of  golden  is  a  colour  wliich 
may  very  fairly  rank  with  red  and  orange.  On  the  other 
hand,  I  have  allowed  all  the  greens,  though  many  of  them 
are  not  colour-words  at  all,  and  though  the  number  of 
objects  which  may  properly  be  called  green  is  out  of  all 
proportion  to  the  number  of  objects  which  may  properly 
be  called  red.  The  true  significance  of  the  list  is  best 
seen  by  comparing  the  2  5  Uues  with  the  151  reds.  To 
adopt  the  statistical  form,  we  might  say  (if  we  chose  to 
reckon  the  unreckonable)  that  red  is  500  per  cent,  more 
poetical  than  blue ! 

For  comparison  with  these  results,  I  have  also  extracted 
the  colour- words  from  Mr.  Tennyson's  "  Princess,"  and  I 
find  they  stand  in  the  following  proportions : — Bed  occurs 
10  times,  crimson  3,  rosy  3,  rosed  (as  an  adjective)  once, 
imhy  once,  and  ruhric  once ;  while  the  verb  to  redden  has 
also  one  mention.  Golden  is  employed  1 3  times,  gold  7, 
gilded  3,  gilt  twice,  yellow  once,  orange  once,  and  the  verb 
to  gild  once.  Purple  occurs  6  times,  purpled  once,  and  em- 
purpled once.  Total  of  the  red-end  epithets,  56.  On  the 
other  hand,  green  is  used  5  times  (not  always  as  a  colour 
term).  Hue  once,  azure  three  times,  lilac  once,  and  violet 
once.  Total  of  the  violet-end  epithets,  ii.  So  that  Mr. 
Tennyson  also  finds  red  and  yellow  just  five  times  as 
poetical  as  green  and  blue. 

There  are,  however,  some  other  more  useful  deductions 
to  be  made  from  the  above  lists.  Observe,  in  Mr.  Swin- 
burne's case,  the  want  of  variety,  the  paucity  of  colour 
terms  as  a  whole — the  total  absence  of  orange^  lilac,  pink, 
azure,  saffron,  vermilion,  or  lavender.  This  absence  is  due 
to  the  fact  that  Mr.  Swinburne  faithfully  echoes  the  old 
ballad  poetry,  with  its  relatively  poor  but  strong  voca- 
bulary— its  preference  of  bold  outline  to  finished  detail. 
There  are  none  of  the  conventional  prettinesses  of  the 
eighteenth  century ;  none  of  the  refined  distinctions  of  our 
modern  miniature  word-painters.  Mr.  Tennyson  puts  in 
colour  phrases  with  the  fidelity  of  a  Dutch  landscape  ; 


266  THE  COLOUR-SENSE. 

but  Mr.  Swiuburne  throws  on  his  broad  contrasts  with  the 
rich  sensuousness  of  an  Egyptian  or  Mediaeval  colourist. 

Observe,  too,  the  preponderance  in  both  poets  of  gold 
and  golden.  The  secret  of  this  peculiarity  is  to  be  found 
in  the  emotional  associations  of  costliness  which  the  words 
suggest.  So  we  find  the  poets  (especially  the  common- 
place) are  fond  of  silvery  locks,  coral  lips,  sapphire  seas, 
ruby  wine,  emerald  eyes,  amber  tresses,  ebon  locks,  pearly 
teeth,  and  ivory  brows.  All  these  points  serve  to  elucidate 
the  real  nature  of  the  poetic  colour-vocabulary.  It  is 
archaic,  it  seeks  immediate  effect,  and  it  lays  stress  upon 
associated  emotions. 

In  order  further  to  impress  these  facts,  I  have  analysed 
a  few  examples  of  well-known  English  poetry,  and  ex- 
tracted the  colour  terms,  or  words  bearing  on  colour,  and 
with  the  following  results  : — 

The  first  two  books  of  Mr.  E.  T.  Palgrave's  "Golden 
Treasury  of  Songs  and  Lyrics,"  embracing  the  Elizabethan 
and  Miltonic  periods,  contain  :  pure  colour-epithets — red  8 
times,  green  6,  hlne  i6,  yelloiu  4  ;  impure  colour-epithets — 
hhishing  2,  crimson  2,  ruby  2,  rermeil  2,  hricky  i,  sanguine 
I,  rosy  3,  cramasie  i,  russet  i, purple  4,  orange  i,  saffron  i, 
golden  13,  gilded  I,  greenish  i,  and  azure  I.  White  occurs 
in  18  places,  Hack  in  6,  snowy  2,  whiter  i,  sable  4,  ebon  i, 
swart  I,  grey  3,  broion  2,  and  nut-brown  i.  Among  con- 
crete coloured  objects,  flower  is  mentioned  28  times,  jpos?/ 
twice,  and  blossom  once;  rose  21,  lily  7,  daffodil  2,  daisy  3, 
violet  /\.,  primrose  2,  cowslip  i,  may  i,  pansy  i,  woodbine  i, 
jessamine  i,  croiv-toe  i,  pink  i,  garland  4,  and  flowery  2. 
Cherry  occurs  6  times.  Gold  counts  for  6,  iwarl  6,  diamond 
I,  coral  5,  amber  2,  sapphire  3,  silver  8,  ivory  i,and  crystal 
8.  Sunset  and  rainbow  are  mentioned  once  each.  The 
only  other  words  suggesting  colour  are  ensaffron  and 
variable  in  the  sense  of  variegated. 

This  list,  I  think,  serves  to  show  two  or  three  of  our 
main  points.  In  the  first  place,  it  is  quite  clear  that  if 
we  take  the  various  red  and  yellow  adjectives,  and  their 


GROWTH  OF  THE  COLOUR-VOCABULARY.      267 

corresponding  concretes,  they  enormously  outnumber  the 
greens  and  blues.  Next,  it  is  instructive  as  showing  how- 
unfair  is  an  enumeration  by  simple  epithets  alone.  Again, 
the  number  of  metaphorical  colour  words  which  it  contains 
must  strike  us  at  once.  And,  lastly,  the  number  of  allu- 
sions to  gems,  or  their  organic  equivalents,  is  very  great. 

Gray's  "  Bard  "  yields  as  follows : — crimson,  ruddy,  hlusJi- 
ing,  and  golden,  once  each,  sable  twice.  Shelley's  "  Skylark," 
golden  twice,  purple,  green,  blue,  white,  and  silver,  once 
each.  Shelley's  "  Euganean  Hills,"  green  three  times,  red, 
purple,  and  golden  twice  each,  crimson,  blue,  azure,  sapphire- 
tinted,  black  and  grey  once  each.  Total,  red  and  yellow 
14  times,  blue  and  green  8  times.  I  obtain  pretty  similar 
proportions  in  many  other  cases. 

And  now  let  us  turn  to  our  final  question — the  examina- 
tion of  the  Homeric  and  Hebrew  colour- vocabulary. 

As  regards  the  Akhaians,  Mr.  Gladstone  tells  us  that 
they  could  not  have  understood  real  colours  by  their 
apparent  colour  terms,  because  the  words  are  used  so 
loosely.  An  adjective  here  applied  to  a  red  object  is  there 
applied  to  a  black  one.  Here,  green  means  green  ;  there, 
it  means  fresh  or  young.  So  be  it.  Has  Mr.  Gladstone 
never  heard  of  red  blood,  red  skies,  red  bricks,  and  red 
Indians  ?  Do  Englishmen  never  talk  of  a  green  old  age, 
or  Americans  of  green  corn,  which  is  really  pale  yellow  ? 
Is  not  red  blood  confronted  with  sangre  azul,  and  red  wine 
with  the  petit  vin  bleu  ?  When  an  untrained  speaker  talks 
of  purple  does  he  not  mean  violet,  and  when  he  talks  of 
violet  does  he  not  mean  ultramarine  ?  Did  any  man  ever 
really  possess  red  hair  or  blue  eyes  ?  In  short,  are  not 
colour  terms  always  vague,  and  are  they  not  vaguer 
in  the  idealised  language  of  poetry  than  anywhere  else  ? 
The  later  Greeks  were  themselves  aware  of  the  deficiency 
in  their  colour-vocabulary,  as  is  shown  by  a  passage  in 
Athenseus  ("  Deipnosophists,"  xviii.  31).^    Mr.  Gladstone's 

1  My  attention  was  called  to  this  son  Smith  in  "Nature,"  December 
passage  by  a  note  of  Professor  Robert-    6th,  1877. 


268  THE  COLOUR-SENSE. 

microscope  lias  brought  out  one  result,  let  us  see  what 
result  the  comparative  method  will  bring  out  on  the  other 
hand.  I  shall  take  the  liberty  of  dogmatising  in  opposi- 
tion to  his  dogmatism,  and  I  shall  leave  the  decision  be- 
tween us  in  the  hands  of  the  critical  reader. ^ 

The  Homeric  Akhaians  were  a  sub-barbaric  race,  who 
had  reached  the  stage  of  culture  at  which  the  use  of  pig- 
ments is  practised,  but  who  only  employed  red  and  a 
reddish  purple  in  staining  or  dyeing.  Their  colour- vocabu- 
lary is  exactly  accommodated  to  such  a  stage.  One  true 
abstract  adjective  exists  for  the  colour  red ;  two  pigmentary 
adjectives  express  the  red  dye  and  the  reddish  purple  dye  : 
a  second  abstract  adjective  denotes  yellow ;  and  all  other 
hues  are  designated  by  metaphorical  colour-terms.  Fur- 
thermore, light  and  shade  adjectives  and  glitter  adjectives 
naturally  preponderate  over  true  colour  epithets  ;  because 
metals  and  precious  stones,  together  with  such  other 
similar  objects  as  ivory  and  horn,  were  more  prized  than 
dyes  or  pigments. 

The  abstract  red  colour  epithet  is  crutliros.  This  is  an 
ancient  Aryan  word,  whose  deriva(tives  express  the  idea 
of  redness  in  all  the  languages  in  which  they  occur.  It 
would  be  hopeless  now  to  decide  whether  it  was  originally 
a  pigmentary  or  a  metaphorical  adjective.  Long  before 
the  age  at  which  the  Homeric  ballad-writers  lived,  it  had 
become  a  true  abstract  word.  That  it  meant  red  and 
nothing  else  is  clear,  not  only  from  the  cognate  languages, 
but  also  from  its  being  applied  to  only  four  objects, 
namely,  copper  (Iliad,  ix.  365),  nectar  (Iliad,  xix.  38 ; 
Odyssey,  v.  93),  wine  (Odyssey,  v.  165  ;  ix.  163,  208  ;  xii. 
19,  327  ;  xiii.  69;  and  xvi.  444),  and  blood  (Iliad,  x.  484; 
xxi.  21),  every  one  of  which  is  red.      When  we  say  red 

^  Were  this  a  mere  specialist  ques-  them  by  comparison  with  the  language 

tion  of  Greek  scholarship  I  would  not  and  the  arts  of  people  in  a  correspond- 

f  or  a  moment  claim  to  be  heard  upon  ing  stage  of  culture  elsewhere.     The 

it.     I  make  no  pretensions  to  minute  matter  is  one  for  the  ethnologist  and 

classical  knowledge  ;  but  I  can  read  the  psychologist,  not  for  the  professed 

my  Homeric  authors,   and  I    judge  Grecian. 


GROWTH  OF  THE  COLOUR-VOCABULARY.       269 

we  mean  red,  and  not  crimson,  scarlet,  russet,  or  any  sub- 
species. 

Tlie  red  pigmentary  epithet  is  some  compound  of 
phoinix.  What  the  material  so  named  may  have  been 
we  cannot  know  with  certainty ;  but  the  uses  of  the  word 
show  clearly  that  it  was  a  bright  scarlet.  In  Iliad,  iv.  141, 
it  is  mentioned  as  a  stain  employed  in  decorating  ivory 
to  form  an  adjunct  of  chieftainship,  and  its  colour  is  there 
described  as  like  that  of  fresh  blood,  flowing  from  an  open 
wound.  Nothing  could  be  clearer  or  more  explicit  than 
this,  and  nobody  but  a  theory-maker  could  mistake  its 
meaning.  That  one  passage  is  quite  enough  to  show 
that  the  Akhaians  saw  red.  To  suppose  that  a  race 
devoid  of  colour-sense  would  take  the  trouble  to  use  dyes 
is  about  as  rational  as  to  suppose  that  a  race  of  deaf-mutes 
would  spend  their  time  in  the  manufacture  of  pianos. 
Elsewhere  the  word  (or  its  derivative)  is  applied  to  a  red 
horse  and  a  red  lion.  As  a  blood  epithet  it  occurs  in  one 
form  or  another  six  times  (Iliad,  xii.  202,  220;  xvi.  159; 
xviii.  538;  xxiii.  716;  Odyssey,  xviii.  96).  It  is  also 
used  for  cloaks  and  mantles,  which  are  never  called 
erutliTos,  and  for  a  very  good  reason ;  the  pure  abstract 
colour  epithet  is  applied  to  wine,  copper,  and  blood,  which 
are  self-coloured ;  but  the  pigmentary  adjective  is  natu- 
rally given  to  the  artificial  objects  stained  with  it.  Thus 
the  girdle  in  Iliad,  vi.  219;  vii.  305  and  Odyssey,  xxiii. 
201,  is  said  to  be  dyed  with  phoinix.  So,  too,  are  the 
prows  of  ships,  like  the  war-canoes  of  so  many  savage 
tribes,  in  the  phrase  phoinikopareos.  Of  course,  the  word  is 
sometimes  extended  to  naturally-coloured  objects — blood, 
horses,  and  jackals — but  the  primitive  pigmentary  sense 
is  pronounced  throughout,  and  the  transference  is  too 
easy  and  simple  to  call  for  special  explanation. 

A  minor  red  pigmentary  adjective  is  miltqmreos,  also 
applied  to  the  war- canoes.  The  milt  may  very  likely 
have  been  an  ochreous  earth.  It  occurs  in  too  specialised 
a  connection  to  hazard  a  guess  upon  its  exact  hue. 


270  THE  COLOUR-SENSE. 

The  r eddish  purple  pigmentary  adjective  is  porplmreos. 
There  is  very  little  reason  to  doubt  that  this  applies  to 
the  Tyrian  murex  dye.  At  any  rate,  it  was  a  stain  em- 
ployed for  artificial  colouring,  and  its  derivation  is  from  a 
verb  meaning  to  mix  together,  or,  more  literally,  to  middle- 
muddle.  Its  commonest  use  is  in  connection  with  clothing, 
especially  the  clothing  of  the  chieftains.  The  word  is 
employed  as  an  epithet  of  carpets  (Iliad,  ix.  200,  Odyssey, 
XX.  278),  coverlets  (Iliad,  xxiv.  643),  mantles  (Odyssey,  xix. 
225),  cloaks  (Iliad,  viii.  221,  Odyssey,  viii.  85),  clothing 
(Odyssey,  xiii.  108),  gowns  (Iliad,  xxiv.  796),  the  web  in 
spinning  (Iliad,  iii.  125  ;  xxii.  441),  and  the  wool  on  the 
distaff  (Odyssey,  vi.  53,  306).  It  is  also  applied  to  a  sort 
of  cricket  ball  (Odyssey,  viii.  373).  In  all  these  cases,  it 
refers  to  objects  actually  dyed  with  the  pigment.  As  a 
secondary  colour  epithet  it  occurs  with  reference  to  the 
purple  rainbow  (Iliad,  xvii.  547),  the  purple  stream  of 
blood  (Iliad,  xvii.  361),  the  purple  sea  (Iliad,  i.  482,  and 
three  times  elsewhere),  and  the  purpling  of  the  soul  in 
terror  (Iliad,  xxi.  551). 

The  other  red  epithets  are  metaphorical.  They  include 
"  rose-like  "  rhodoeis,  "  wine-faced "  oinops,  and  "  pretty- 
cheeked  "  kallipareos. 

The  abstract  yellow  colour  epithet  is  xantJios.  It  is 
applied  to  human  hair,  to  horses,  and  to  the  brook  of  that 
name.  But  in  the  Homeric  poems,  as  in  all  other  poetical 
writing,  yeUow  is  generally  described  by  gold  or  golden. 

Blue  has  only  two  words,  both  metaphorical.  The  first, 
hualdnthinos,  is  derived  from  some  flower,  possibly  a 
hyacinth.  It  occurs  but  sparingly.  The  second  word,  ioeis 
or  ioeides,  is  undoubtedly  the  colour  of  the  violet — that  is, 
ultramarine.  The  sea  is  three  times  spoken  of  as  "  violet- 
faced"  (Iliad,  ix.  29S ;  Odyssey,  v.  55  ;  xi.  106),  and  it  can- 
not be  denied  that  the  sea  is  sometimes  (though  rarely)  blue. 
'  Violetish '  is  also  used  of  blue  steel.  We  must  remember, 
in  this  connection,  that  the  pottery  of  Troy  and  Mycense 
is  coloured  red  and  yellow,  never  blue.  But  once,  in 
Odyssey,   iv.   135,  we  get  the  startling  word,  iodnephcs, 


GROWTH  OF  THE  COLOUR-VOCABULARY.      271 

"  violet-darkened,"  or  dyed  blue,  applied  to  wool.  This 
would  seem  as  though  towards  the  close  of  the  epic  period, 
w^hen  the  Odyssean  ballads  w^ere  composed,  a  blue  dye 
began  to  make  its  appearance.  On  this  point  we  shall  find 
hereafter  a  Hebrew  analogy. 

Green  is  always  designated  by  "grass-like"  {kliloros). 
The  derivation  is  from  kliloS,  herbage.  The  word  is  seldom 
applied  to  literally  green  objects,  because  such  are  generally 
leaves  or  other  vegetal  products,  of  which  the  name  alone 
is  sufficient  to  describe  the  colour.  The  ballad-maker 
loves  to  dwell  on  red  wine,  scarlet  robes,  purple  carpets, 
golden  helmets,  glistening  bronze  ;  but  why  should  he 
need  to  tell  us  about  the  common  green  leaves  or  the 
blue  sky  overhead  ?  These  things  belong  to  the  poetry  of 
civilised  man,  the  town  dweller ;  but  they  find  no  natural 
place  in  the  rude  songs  which  tell  the  tale  of  savage  royalty 
and  bloody  fights. 

Herein  we  get  the  real  secret  of  the  Akhaian  colour 
nomenclature.  The  many  brilliant  objects  of  external 
nature  for  which  we  require  such  varied  names — the 
flowers,  the  birds,  the  butterflies — these  were  of  little 
importance  in  the  eyes  of  those  bloodthirsty  warriors, 
whose  greatest  joy  was  the  hharmi,  the  battle-ecstasy,  the 
delight  in  slaying.  Only  a  very  few  flowers  have  separate 
names  in  the  poet's  vocabulary:  as  a  rule  mere  vague 
references  sufiice  for  all  his  needs.  The  objects  which  he 
most  wishes  to  describe  are  men,  horses,  cattle,  whose 
hues  are  indefinite,  impure,  and  very  variable  in  different 
individuals.  Bronze,  gold,  silver,  garments,  war-canoes, 
royal  furniture,  sceptres,  and  rude  palaces,  these  supply 
him  with  a  few  epithets  of  dyes  or  natural  colours.  But 
when  he  turns  to  nature,  it  is  the  great  wholes  alone 
which  attract  his  attention ;  the  sea,  white,  or  blue,  or 
green,  or  grey,  or  purple,  in  its  changeful  moods ;  the  sky, 
coppery,  or  azure,  or  leaden,  or  black  with  storm-clouds, 
or  crimson  with  the  sunset,  or  gilded  with  the  rays  of 
daAvn.      Earth,  mountains,  rivers,  sands,  and  rocks,  all 


272  THE  COLOUR-SENSE. 

these  afford  him  no  fixed  and  regular  sensations.  Hence 
his  language  is  necessarily  indefinite  and  vague.  The 
epithet  that  suited  the  sea  in  this  line  suits  the  sky  in 
that.  What  is  the  colour  of  a  horse,  of  a  cow,  of  the 
human  race,  of  water,  of  clouds,  of  the  ship  under  weigh  ? 
Eed,  or  black,  or  white,  or  grey,  or  what  you  will. 

In  truth,  the  primitive  man  shows  his  acute  colour 
perceptions  by  the  accurate  manner  in  which  he  detects 
faint  undertones  of  hues  hardly  suspected  at  a  first  rough 
glance.  How  sharp  is  the  eye  which  notes  the  almost 
imperceptible  tinge  of  greenness  in  the  face  of  fear,  and 
likens  it  at  once  to  the  full  green  of  grass  ?  How  keen  is 
the  sense  which  catches  the  sliq-ht  difference  of  shade 
between  the  black  Douoias  and  the  red  Doudas,  between 
the  O'Connor  Don  and  the  O'Connor  Eoe !  The  most 
insignificant  trace  of  ruddiness  in  the  soil  entitles  a  place 
to  be  called  Edom,  Eriithrai,  or  Rutland;  the  merest 
suspicion  of  yellow  gives  us  such  names  as  Xantlws  and 
Hoang  Ho.  In  short,  if  one  object  be  a  little  darker  than 
anotlier,  the  quick-minded  savage  calls  it  black  ;  if  it  have 
a  tiny  infusion  of  blueness,  he  says  it  is  sky-faced. 

As  for  the  indirect  traces  of  colour-perception  in  the 
Homeric  poems,  I  need  only  point  to  such  casual  references 
in  the  Iliad  as  "  saffron-robed  Dawn  "  (Iliad,  viii.  i ) ;  the 
many-coloured  metals  of  Agamemnon's  armour  (xi.  15); 
the  jewelled  girdle  of  Aphrodite  (xiv.  181);  the  silver, 
gold,  bronze,  and  tin  of  AkhiUes'  shield  (xviii.  474) ;  or 
the  cup,  "  wrought  by  cunning  Sidonian  workmen,  and 
brought  by  Phoenician  men  across  the  sky-blue  sea" 
(xxiii..743).  Then  there  are  the  occasional  references  to 
flowers,  roses,  violets,  hyacinths,  and  crocuses.  But 
perhaps  the  best  proof  of  all  is  that  afforded  by  the 
wardrobe  of  Hekabe,  "wherein  were  her  many-coloured 
{pam'poikiloi)  robes,  Sidonian  women's  work,  which  god- 
like Alexander  brought  himself  from  Sidon-land,  sailing 
across  the  mighty  sea."  Amongst  all  these,  Hekabe  chose 
for  Athene  "  that  which  was  loveliest   in ,  figured   dyes 


GROWTH  OF  THE  COLOUR-VOCABULARY.     273 

{poikilmasin),  and  largest  eke,  and  as  some  star  it  shone ;  " 
and  rosy-cheeked  Theano  laid  it  on  the  knees  of  the 
golden-haired,  hazel-eyed  goddess.  How  singularly  appro- 
priate all  these  phrases  would  sound  in  the  mouth  of  a 
poet  who  did  not  know  one  colour  from  another  ! 

And  now  let  us  pass  on  to  Geiger's  instance  of  the 
ancient  Hebrews.  Here  I  can  only  trust  to  the  Authorised 
Version  of  the  early  books,  for  I  am  no  Hebraist ;  but  I 
have  secured  the  kind  assistance  of  a  distinguished 
specialist,  the  Eev.  T.  K.  Cheyne,  and  I  venture  to  submit 
my  results  as  follows  : — 

The  Hebrews  of  the  kingly  age  were  one  step  in  advance 
of  the  Homeric  Akhaians,  as  regards  their  employment  of 
pigments,  and  the  wealth  of  their  colour- vocabulary.  This 
might  naturally  be  expected  from  their  closer  connection 
with  the  civilised  communities  of  Egypt  and  Assyria. 
They  appear  to  have  employed  three  pigments,  a  red,  a 
purple,  and  a  blue ;  and  they  had  a  word  in  common  use 
for  OTcen. 

o 

The  history  (or  legend)  of  the  Tabernacle  gives  an  account 
of  the  objects  to  be  offered  for  sacred  purposes,  which  in- 
clude "  gold,  and  silver,  and  brass ;  and  blue,  and  purple, 
and  scarlet;  and  fine  linen,  and  goats'  hair;  and  rams 
skins  dyed  red,  and  badgers'  skins  ;  and  shittim  wood ;  oil 
for  the  light,  spices  for  anointing  oil,  and  for  sweet  incense; 
onyx  stones,  and  stones  to  be  set  in  the  ephod  and  in  the 
breastplate."  ^  The  curtains  of  the  Tabernacle  were  to  be 
made  of  "  fine  twined  linen,  and  blue  and  purple  and 
scarlet,"  ^  and  fringed  with  "  loops  of  blue."  The  same 
stereotyped  conjunction  of  "blue  and  purple  and  scarlet" 
reappears,  with  true  Hebrew  monotony,  in  the  veil  (Exod. 
xxvi.  31),  the  hanging  for  the  door  (xxvi.  36),  the  gate 
of  the  court  (xxvii.  16),  and  elsewhere  during  the  subse- 

^  Exod.  XXV.  4-7.     I  have  quoted    course,  the  date  of  its  composition  is 
this  passage  entire,  because  it  illus-    purely  conjectural.  r 

trates  well  the  aesthetic  stage  of  the        2  W^i^,  xxvi.  i. 
time  when  it  was  written,  though,  of 

S 


274  THE  COLOUR-SENSE. 

quent  chapters  no  less  than  nine  times.  Various  minor 
portions  of  the  sacerdotal  costume  are  specially  restricted 
to  one  hue.  Gold  and  other  precious  objects  occur  in 
profusion. 

The  account  of  Solomon's  Temple  shows  the  same  three 
prevalent  colours,  and  no  others,  used  as  pigments.^  As 
before,  the  veil  was  made  "  of  blue  and  purple  and  crim- 
son and  fine  linen,"  ^  under  the  direction  of  a  half-caste 
Phoenician,  whose  father  was  a  man  of  Tyre,  "  skilful  to 
work  in  gold  and  in  silver,  in  brass,  in  iron,  in  stone,  and 
in  timber ;  in  purple,  in  blue,  and  in  fine  linen,  and  in 
crimson ;  also  to  grave  any  manner  of  graving,  and  to  find 
out  every  device."^  To  multiply  examples  would  only 
prove  tedious  to  the  reader,  without  adding  materially  to 
the  arsjument. 

I  learn  from  Mr.  Cheyne  that  these  words  might  be 
more  correctly  translated  Uue-purple,  red-purple,  and  crim- 
son. The  first  two  colours  were  obtained  from  mollusca, 
and  the  third  from  the  cochineal-insect.  The  derivations 
of  the  words  meaning  hlue-purple  and  red-purple  are  un- 
known, but  they  occur  in  the  same  combination  in  Assy- 
rian ;  that  of  the  third  is  from  the  Hebrew  word  for  "  a 
w^orm."  The  term  translated  crimson  in  the  Chronicles  is 
a  later  name  for  the  same  colour  which  is  called  scarlet  in 
Exodus,  and  its  origin  is  perhaps  Persian. 

Furthermore,  the  allusions  to  precious  stones  (whether 
the  words  referring  to  them  be  correctly  translated  in 
every  case  or  otherwise)  clearly  exhibit  the  aesthetic 
standing  of  the  people.  The  breastplate  of  judgment  con- 
tained twelve  jewels — sardius,  topaz,  carbuncle,  emerald, 
sapphire,  diamond,  ligure,  agate,  amethyst,  beryl,  onyx, 


1  I  give  no  opinion  upon  the  chro-  colour  perception  among  the  Hebrews 

nological    and    historical    question,  as  the  existence  of  Agamemnon  or  the 

because  I  am  not  competent  to  form  personality  of  the  supposed   Homer 

one.     The  date  of  the  writer  and  the  with  the  same  fact  among  the  early 

credibility  of  the  narrative,  however,  Akhaians. 
have  as  little  to  do  with  the  fact  of        ^  aChron.  iii.  15,  etal.    3  ibid,  ii.  14. 


GROWTH  OF  THE  COLOUR-VOCABULARY.      275 

and  jasper.i  The  jewel  called  sapphire  was  certainly 
blue ;  for  the  "  God  of  Israel "  is  described  as  standing  on 
"  a  paved  work  of  sapphire  stone  " — in  other  words,  on  the 
solid  firmament.^  Solomon's  Temple  was  "  garnished  with 
precious  stones  for  beauty,"^  and  other  notices  of  the 
same  sort  occur  elsewhere. 

Besides  these  directly  aesthetic  accounts,  we  find  scat- 
tered colour  terms  throughout  all  the  books.  In  the  very 
early  myth  of  Joseph  we  read  of  a  "  coat  of  many  colours."* 
"  Eibbands  of  blue "  were  enjoined  on  the  people  in  the 
desert.^  Eahab  agrees  with  the  spies  to  hang  out  "  scarlet 
thread  "  as  a  signal.^  Tamar  wears  a  "  garment  of  divers 
colours,  for  with  such  robes  were  the  king's  virgin  daugh- 
ters apparelled."'^  Aholah,  in  Ezekiel's  fable,  doted  on  her 
lovers,  the  Assyrians,  who  were  ''clothed  in  blue;"^  and 
Aholibah  on  "the  images  of  the  Chaldeans  pourtrayed 
with  vermilion,"  "exceeding  in  dyed  attire  upon  their 
heads."  Much  doubt  hangs  over  the  first  and  fourth  of 
these  renderings;  but  I  give  them  in  the  words  of  the 
Authorised  Version  (preserving  the  traditional  belief)  for 
what  they  may  be  worth. 

Green,  however,  is  never  mentioned  during  the  native 
kingly  period  as  a  decorative  colour.  "  Green  pastures  " 
in  Psalm  xxiii.  2,  "might  be  better  translated  'tender 
grass ; '  "  but  we  must  remember  that  almost  all  words  for 
green  originally  refer  to  growth  or  freshness.  On  the 
other  hand,  the  "green  herb"  in  Gen.  i.  30  (literally 
"  every  greenness  of  herbage")  has  the  notion  of  colour 
original,  according  to  Mr.  Cheyne,  "  or  at  least  early 
reached  by  usage."  The  corresponding  word  in  Arabic,  a 
leading  scholar  in  that  language  informs  us,  means  rather 
grey  than  green :  and  this  vagueness  is  exactly  paralleled 
by  that  of  the  Greek  kliloros.  Both  cases  show,  not  that 
green  was  unperceived,  but  that  it  ranked  low  in  assthetic 
value. 

1  Exod.  xxix,  17.     2  Ibid.,  xxiv.  10.        ^  yvir.b.  xv.  3?.       ^  Josh.  ii.  18. 
^  2  Chron.  iii.  6.      ^  Qgu_  xxxvii.  3.        ^2  Sam.  xiii.  18.     ^  ^-^^ik..  xxiii.  6. 


2/6  THE  COLOUR-SENSE. 

Yet  though  green  found  no  place  in  the  decorations  of 
the  Tabernacle  or  the  Temple,  it  is  once  mentioned  in 
the  Authorised  Version,  among  the  ornaments  of  a  foreign 
court,  when  Ahasuerus  the  king  feasted  in  Shushan  the 
palace,  "  where  were  white,  green,  and  blue  hangings, 
fastened  with  cords  of  fine  linen  and  purple  to  silver 
rings  and  pillars  of  marble :  the  beds  were  of  gold  and 
silver,  upon  a  pavement  of  red,  and  blue,  and  white,  and 
black  marble."  ^  Now,  though  Mr.  Cheyne  tells  me  that 
modern  philology  has  decided  in  favour  of  the  translation 
"  cotton "  instead  of  "  green,"  yet  when  we  examine  the 
peculiar  position  of  this  word  in  the  sentence,  and  then 
recollect  the  ancient  Persian  fondness  for  green,  with  the 
constant  appearance  of  that  hue  on  the  Babylonian  and 
Ninevite  enamelled  bricks,  I  can  scarcely  help  believing 
that  in  this  case  the  traditional  rendering  closely  represents 
the  truth.  Mr.  Cheyne  himself,  indeed,  inclines  to  think 
that  though  the  word  means  etymologically  "  cotton,"  yet 
some  idea  of  colour  (he  suggests  "  variegated ")  is  mixed 
up, with  it  in  practice.  Perhaps,  then,  we  may  have  here 
an  analogous  advance  to  that  of  the  Akhaians  from  red, 
purple,  and  yellow  decorations  to  the  artistic  employment 
of  blue.  In  any  case,  we  can  scarcely  doubt  that  the 
Hebrews  after  the  Captivity  must  in  great  part  have 
adopted  the  aesthetic  standard  of  their  Semitic  and 
Aryan  conquerors. 

One  final  example  of  Mr.  Gladstone's  method  must  be 
given  apropos  of  the  Hebrew  colour-sense.  Ezekiel  de- 
scribes in  glowing  language  the  truly  oriental  vision  in 
which  his  poetic  eye  beheld  in  imagination  the  glories  of 
the  God  of  Israel,  "Above  the  firmament,"  says  the 
prophet,  "  was  the  likeness  of  a  throne,  as  the  appearance 
of  a  sapphire  stone :  and  upon  the  likeness  of  the  throne 
was  the  likeness  as  the  appearance  of  a  man  upon  it. 
And  I  saw  as  the  colour  of  amber,  as  the  appearance  of 
fire  round  about  within  it  .  .  .    and  it  had  brightness 

1  Esther  i.  7. 


GROWTH  OF  THE  COLOUR-VOCABULARY.      277 

round  about.  As  tlie  appearance  of  the  bow  that  is  in  the 
cloud  in  the  day  of  rain,  so  was  the  appearance  of  the 
brightness  round  about  it."  ^  Mr.  Gladstone  quotes  in  part 
this  perfectly  pellucid  passage,  and  thus  comments  upon 
it :  "  Which  cannot  be  explained  but  by  supposing  that, 
for  the  eye  of  the  prophet,  red  was  the  fundamental,  and 
exclusively  prevailing,  colour  of  the  rainbow."  Any  un- 
prejudiced person  would  have  imagined  that  the  w^ords 
"  could  not  be  explained  but  by  supposing "  the  prophet 
to  mean  exactly  what  he  says — that  a  halo  of  every  hue 
in  the  rainbow  surrounded  the  sapphire  throne,  where  the 
God  of  Israel  was  seated,  begirt  with  amber  flames,  looking 
down  upon  the  work  which  was  like  unto  the  colour  of  a 
beryl,  and  planting  His  foot  on  the  firmament,  whose 
appearance  was  of  terrible  crystal.  But  literal  interpreta- 
tion will  sometimes  lead  men  into  a  strange  confusion  of 
the  obvious. 

As  for  the  Yedas,  I  shall  not  attempt  to  deal  with  them. 
That  "  book  with  seven  seals,"  as  Professor  Max  Milller 
calls  it,  can  be  easily  made  to  prove  that  black  is  white, 
or  vice  versa :  and  therefore  to  juggle  with  its  colours  is 
a  mere  piece  of  simple  conjuring.  If  the  reader  believes 
that  the  case  for  Dr.  Magnus  has  broken  down  so  far,  he 
will  hardly  attach  much  importance  to  the  doubtful 
utterances  of  the  Sanskrit  Scriptures. 

And  now  that  our  review  is  completed,  it  may,  perhaps, 
appear  to  some  readers  that,  in  combating  this  "  historical 
development "  theory,  I  have  been  really  doing  battle,  like 
Don  Quixote,  with  a  perfectly  harmless  foe.  Whereto  I 
would  respectfully  answer  that  I  seem  rather  to  be  per- 
forming the  less  romantic  part  of  Sancho  Panza.  Sundry 
learned  writers  having  discovered  an  imaginary  giant,  it 
becomes  my  humble  duty,  as  a  common-sense  critic,  to 
point  out  that  the  monstrous  being  is,  in  fact,  nothing 
more  nor  less  than  a  windmill.  Such  a  task  may  be  un- 
grateful and  inglorious  enough,  but  it  remains  none  the 

^  Ezekiel  i.  26. 


278  THE  COLOUR-SENSE. 

less  necessary  for  the  prevention  of  further  hallucinations 
on  the  same  subject  in  future.  When  an  honest  and 
truthful  knight  solemnly  assures  us  that  he  has  met  with 
a  genuine  giant,  the  world  at  large  naturally  accepts  his 
statement  in  good  faith,  and  goes  on  believing  it  until 
some  lowly  squire  comes  forward  to  sift  the  evidence  upon 
which  his  assertion  is  based. 

Finally,  I  hope  that  besides  the  negative  task  of  demo- 
lition, we  have  been  able,  in  the  course  of  our  argument, 
to  build  up  some  new  and  positive  constructive  work, 
which  will  throw  fresh  light  both  on  aesthetic  development 
and  on  the  growth  of  special  vocabularies.  This  must  be 
my  excuse  for  a  digression  which  might  at  first  sight  have 
appeared  to  be  leading  us  too  far  from  the  central  subject, 
on  whose  consideration  we  are  here  engaged. 


(    279    ) 


CHAPTER  XIV. 

SUMMARY  AND   RECAPITULATION. 

Now  that  we  have  completed  our  survey  of  the  Origin 
and  Development  of  the  Colour-Sense,  we  may  briefly 
sum  up,  in  a  dogmatic  form,  the  main  results  to  which  we 
have  been  led  in  the  course  of  our  investigation. 

Colour,  viewed  objectively,  consists  in  the  different 
rapidity  and  wave-length  of  various  sethereal  undulations. 
These  undulations,  taken  in  their  totality,  are  called 
light ;  taken  in  their  several  component  parts,  they  are 
called  colour. 

The  earliest  animal  eyes  are  cognisant  of  light  and  its 
negation  only.  Next,  probably,  came  the  discrimination 
of  form.  Last  of  all  was  developed  the  qualitative  per- 
ception of  colour. 

This  perception  was  apparently  first  aroused  in  the  case 
of  insects  by  the  hues  of  flowers.  The  flowers  were  them- 
selves developed  by  the  action  of  the  insect  eyes,  and 
they  reacted  simultaneously  upon  the  senses  of  the  insects 
to  whose  selection  they  were  due. 

In  simple  marine  animals,  the  perception  of  colour  was 
probably  first  aroused  by  the  animal  organisms  in  their 
environment.  From  them  it  was  handed  down  to  the 
fishes  and  reptiles,  and  more  remotely  to  the  birds  and 
mammals.  In  the  latter  case,  however,  the  sense  may 
have  been  quickened  and  kept  alive  by  its  exercise  upon 
coloured  fruits,  which  were  produced  by  the  selective 
action  of  these  great  classes  themselves. 

The  general  existence  of  a  colour-sense  in  insects  and 


28o  THE  COLOUR-SENSE. 

vertebrates  is  shown,  in  some  cases,  by  direct  experi- 
ment, in  other  cases  by  a  large  number  of  inferen- 
tial proofs.  It  is  a  hypothesis  which  explains  all  the 
facts  in  the  colouration  of  organic  bodies,  and  without 
which  the  facts  become  a  mere  chaos  of  inexplicable 
caprices.' 

The  constant  employment  of  the  colour-percipient  struc- 
tures in  the  search  for  food,  amongst  the  flower-haunting 
and  fruit-eating  animals,  would  ultimately  lead  to  the 
strengthening  of  those  structures,  and,  consequently,  to  the 
development  of  a  concomitant  pleasure.  This  pleasure 
shows  itself  in  the  form  of  a  taste  for  colour.  Such  a 
taste  is  found  in  a  large  majority  of  the  species  so  circum- 
stanced. It  becomes  manifest  partly  in  the  selection  of 
bright  foods,  partly  in  a  general  love  for  brilliant  objects, 
but  most  of  all  in  the  choice  of  gaily-coloured  partners. 
To  this  cause  we  owe  the  beauty  of  butterflies,  birds,  and 
many  other  animals. 

Besides  this  direct  reaction  of  the  colour-sense  upon 
the  external  appearance  of  the  creatures  which  possess  it, 
an  indirect  reaction  is  exerted  by  the  constant  killing  off 
of  those  individuals  whose  colouration  specially  exposes 
them  to  attack,  and  the  survival  of  those  individuals 
whose  colouration  affords  them  any  means  of  protection, 
either  through  inconspicuousness,  mimicry,  or  any  other 
mode.  In  this  manner  a  large  number  of  animals  have 
acquired  the  hues  which  they  now  display. 

The  quadrumana,  being  frugivorous  animals,  possess 
the  colour-sense  in  a  high  degree.  They  show  a  consider- 
able taste  for  bright  colours,  and  their  own  appearance 
often  betrays  the  action  of  sexual  selection. 

Man,  the  descendant  of  the  frugivorous  quadrumana, 
also  possesses  a  very  perfect  colour-sense,  which  is  equally 
evolved  in  all  varieties  of  the  species,  from  the  highest  to 
the  lowest.  A  supposed  linguistic  proof  to  the  contrary 
is  not  countenanced  by  the  other  facts  of  the  case.  Direct 
investigations   show   that    all    existino:   men  have    like 


SUMMARY  AND  RECAPITULATION.  281 

colour-perceptions ;  and  historical  inquiry  shows  that  the 
same  is  true  of  all  earlier  races. 

Man  derives  from  his  frugivorous  ancestors,  not  onlv 
the  perception,  but  also  the  love  of  colour.  This  love  is 
shown  first  in  personal  decoration,  and  is  afterwards 
extended  to  the  arts  in  general.  The  taste  for  colour  at 
length  affects  almost  every  object  of  human  industry ;  but 
it  must  all  be  originally  referred  to  the  habits  of  our  fru- 
givorous ancestors. 

The  vocabulary  of  colour,  like  all  other  vocabularies, 
springs  up  in  proportion  to  the  needs  of  the  various 
languac^es. 

The  arts  employ  chiefly  the  colours  which  are  least 
common  in  external  nature,  and  which  are  also  those 
employed  by  fruits  and  flowers  for  the  attraction  of 
animals  generally.  Poetry  likewise  uses  them  in  the  same 
proportions,  but  in  an  ideal  form.  The  most  advanced 
arts,  however,  use  colour  in  more  balanced  quantities. 
But  all  art,  decorative  or  imitative,  retains  to  the  last 
somewhat  of  its  original  character,  as  a  direct  stimulant  of 
simple  chromatic  pleasure. 

Thus  the  colour-sense,  in  its  origin  and  its  results,  is 
seen  to  be  one  and  continuous  throughout.  The  highest 
aesthetic  products  of  humanity  form  only  the  last  link 
in  a  chain  whose  first  link  began  with  the  insect's  selec- 
tion of  bright-hued  blossoms.  The  whole  long  series 
may  be  briefly  summed  up  in  some  such  formula  as  the 
following : — 

Insects  produce  flowers.  Flowers  produce  the  colour- 
sense  in  insects.  The  colour-sense  produces  a  taste  for 
colour.  The  taste  for  colour  produces  butterflies  and 
brilliant  beetles.  Birds  and  mammals  produce  fruits. 
Fruits  produce  a  taste  for  colour  in  birds  and  mammals. 
The  taste  for  colour  produces  the  external  hues  of  hum- 
ming-birds, parrots,  and  monkeys.  Man's  frugivorous 
ancestry  produces  in  him  a  similar  taste ;  and  that  taste 
produces  the  various  final  results  of  human  chromatic  arts. 


282  THE  COLOUR-SENSE. 

What  a  splendid  and  a  noble  prospect  for  humanity  in 
its  future  evolutions  may  we  not  find  in  this  thought,  that 
from  the  coarse  animal  pleasure  of  beholding  food  man- 
kind has  already  developed,  through  delicate  gradations, 
our  modern  disinterested  love  for  the  glories  of  sun- 
set and  the  melting  shades  of  ocean,  for  the  gorgeous 
pageantry  of  summer  flowers,  and  the  dying  beaut}^  of 
autumn  leaves,  for  the  exquisite  harmony  which  reposes 
on  the  canvas  of  Titian,  and  the  golden  haze  which  glim- 
mers over  the  dreamy  visions  of  Turner !  If  man,  base 
as  he  yet  is,  can  nevertheless  rise  to-day  in  his  highest 
moments  so  far  above  his  sensuous  self,  what  may  he  not 
hope  to  achieve  hereafter,  under  the  hallowing  influence 
of  those  chaster  and  purer  aspirations  which  are  welling 
up  within  him  even  now  toward  the  perfect  day ! 


THE  END. 


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